[Discover] DiscoverContainer cleanup (#163015)

## Summary

Just some small cleanups related to the `DiscoverContainer`
implementation as a followup to #160036.

src/plugins/discover/public/application/main/components/top_nav/discover_topnav.test.tsx

@@ -18,8 +18,8 @@ import { getDiscoverStateMock } from '../../../../__mocks__/discover_state.mock'
 import { DiscoverMainProvider } from '../../services/discover_state_provider';
 import type { SearchBarCustomization, TopNavCustomization } from '../../../../customizations';
 import type { DiscoverCustomizationId } from '../../../../customizations/customization_service';
-
 import { useDiscoverCustomization } from '../../../../customizations';
+
 setHeaderActionMenuMounter(jest.fn());
 
 jest.mock('@kbn/kibana-react-plugin/public', () => ({
@@ -76,22 +76,20 @@ describe('Discover topnav component', () => {
     mockUseCustomizations = false;
     jest.clearAllMocks();
 
-    (useDiscoverCustomization as jest.Mock).mockImplementation(
-      jest.fn((id: DiscoverCustomizationId) => {
-        if (!mockUseCustomizations) {
-          return undefined;
-        }
+    (useDiscoverCustomization as jest.Mock).mockImplementation((id: DiscoverCustomizationId) => {
+      if (!mockUseCustomizations) {
+        return undefined;
+      }
 
-        switch (id) {
-          case 'top_nav':
-            return mockTopNavCustomization;
-          case 'search_bar':
-            return mockSearchBarCustomization;
-          default:
-            throw new Error(`Unknown customization id: ${id}`);
-        }
-      })
-    );
+      switch (id) {
+        case 'top_nav':
+          return mockTopNavCustomization;
+        case 'search_bar':
+          return mockSearchBarCustomization;
+        default:
+          throw new Error(`Unknown customization id: ${id}`);
+      }
+    });
   });
 
   test('generated config of TopNavMenu config is correct when discover save permissions are assigned', () => {

src/plugins/discover/public/components/discover_container/discover_container.test.tsx

@@ -8,9 +8,12 @@
 
 import React from 'react';
 import { render, waitFor } from '@testing-library/react';
-import { DiscoverServices } from '../../build_services';
-import DiscoverContainerInternal, { DiscoverContainerInternalProps } from './discover_container';
-import { ScopedHistory } from '@kbn/core-application-browser';
+import type { DiscoverServices } from '../../build_services';
+import {
+  DiscoverContainerInternal,
+  type DiscoverContainerInternalProps,
+} from './discover_container';
+import type { ScopedHistory } from '@kbn/core-application-browser';
 import { discoverServiceMock } from '../../__mocks__/services';
 import { KibanaContextProvider } from '@kbn/kibana-react-plugin/public';
 import { dataPluginMock } from '@kbn/data-plugin/public/mocks';
@@ -45,7 +48,7 @@ const TestComponent = (props: Partial<DiscoverContainerInternalProps>) => {
 };
 
 const TEST_IDS = {
-  DISCOVER_CONTAINER_INTERNAL: 'data-container-internal-wrapper',
+  DISCOVER_CONTAINER_INTERNAL: 'discover-container-internal-wrapper',
 };
 
 describe('DiscoverContainerInternal should render properly', () => {

src/plugins/discover/public/components/discover_container/discover_container.tsx

@@ -8,9 +8,9 @@
 
 import { EuiFlexGroup, EuiFlexItem } from '@elastic/eui';
 import type { ScopedHistory } from '@kbn/core/public';
-import { euiStyled } from '@kbn/kibana-react-plugin/common';
 import { KibanaContextProvider } from '@kbn/kibana-react-plugin/public';
 import React, { useEffect, useMemo, useState } from 'react';
+import { css } from '@emotion/react';
 import { DiscoverMainRoute } from '../../application/main';
 import type { DiscoverServices } from '../../build_services';
 import type { CustomizationCallback } from '../../customizations';
@@ -31,15 +31,15 @@ export interface DiscoverContainerInternalProps {
   isDev: boolean;
 }
 
-const DiscoverContainerWrapper = euiStyled(EuiFlexGroup)`
+const discoverContainerWrapperCss = css`
   width: 100%;
   height: 100%;
 
   // override the embedded discover page height
   // to fit in the container
   .dscPage {
-    height: 100%
-}
+    height: 100%;
+  }
 `;
 
 export const DiscoverContainerInternal = ({
@@ -70,14 +70,17 @@ export const DiscoverContainerInternal = ({
 
   if (!initialized || !services) {
     return (
-      <DiscoverContainerWrapper>
+      <EuiFlexGroup css={discoverContainerWrapperCss}>
         <LoadingIndicator type="spinner" />
-      </DiscoverContainerWrapper>
+      </EuiFlexGroup>
     );
   }
 
   return (
-    <DiscoverContainerWrapper data-test-subj="data-container-internal-wrapper">
+    <EuiFlexGroup
+      css={discoverContainerWrapperCss}
+      data-test-subj="discover-container-internal-wrapper"
+    >
       <EuiFlexItem>
         <KibanaContextProvider services={services}>
           <DiscoverMainRoute
@@ -87,7 +90,7 @@ export const DiscoverContainerInternal = ({
           />
         </KibanaContextProvider>
       </EuiFlexItem>
-    </DiscoverContainerWrapper>
+    </EuiFlexGroup>
   );
 };
 

src/plugins/discover/public/customizations/customization_types/search_bar_customization.ts

@@ -8,11 +8,11 @@
 
 import type { AggregateQuery } from '@kbn/es-query';
 import type { TopNavMenuProps } from '@kbn/navigation-plugin/public';
-import type { ComponentType, ReactElement } from 'react';
+import type { ComponentType } from 'react';
 
 export interface SearchBarCustomization {
   id: 'search_bar';
   CustomDataViewPicker?: ComponentType;
   PrependFilterBar?: ComponentType;
-  CustomSearchBar?: (props: TopNavMenuProps<AggregateQuery>) => ReactElement;
+  CustomSearchBar?: ComponentType<TopNavMenuProps<AggregateQuery>>;
 }

src/plugins/discover/public/plugin.tsx

@@ -78,7 +78,10 @@ import {
   createProfileRegistry,
 } from './customizations/profile_registry';
 import { SEARCH_EMBEDDABLE_CELL_ACTIONS_TRIGGER } from './embeddable/constants';
-import { DiscoverContainerInternal, DiscoverContainerProps } from './components/discover_container';
+import {
+  DiscoverContainerInternal,
+  type DiscoverContainerProps,
+} from './components/discover_container';
 
 const DocViewerLegacyTable = React.lazy(
   () => import('./services/doc_views/components/doc_viewer_table/legacy')
@@ -430,20 +433,18 @@ export class DiscoverPlugin
     injectTruncateStyles(core.uiSettings.get(TRUNCATE_MAX_HEIGHT));
 
     const isDev = this.initializerContext.env.mode.dev;
-
     const getDiscoverServicesInternal = () => {
       return this.getDiscoverServices(core, plugins);
     };
 
     return {
       locator: this.locator,
-      DiscoverContainer: ({ overrideServices, ...restProps }: DiscoverContainerProps) => {
+      DiscoverContainer: (props: DiscoverContainerProps) => {
         return (
           <DiscoverContainerInternal
-            overrideServices={overrideServices}
             getDiscoverServices={getDiscoverServicesInternal}
             isDev={isDev}
-            {...restProps}
+            {...props}
           />
         );
       },