[SLO] update default feature flag value for slo management (#216919)

## Summary

update default feature flag value for slo management, persist flag state
to callout

src/platform/test/plugin_functional/test_suites/core_plugins/rendering.ts

@@ -378,7 +378,6 @@ export default function ({ getService }: PluginFunctionalProviderContext) {
         'xpack.apm.featureFlags.ruleFormV2Enabled (boolean?)',
         'xpack.observability.unsafe.ruleFormV2.enabled (boolean?)',
         'xpack.slo.experimental.ruleFormV2.enabled (boolean?)',
-        'xpack.slo.experimental.management.enabled (boolean?)',
         /**/
       ];
       // We don't assert that actualExposedConfigKeys and expectedExposedConfigKeys are equal, because test failure messages with large

x-pack/solutions/observability/plugins/slo/common/config.ts

@@ -16,9 +16,6 @@ export const configSchema = schema.object({
       ruleFormV2: schema.object({
         enabled: schema.boolean({ defaultValue: false }),
       }),
-      management: schema.object({
-        enabled: schema.boolean({ defaultValue: false }),
-      }),
     })
   ),
 });

x-pack/solutions/observability/plugins/slo/public/application.tsx

@@ -140,9 +140,9 @@ export const renderApp = ({
 };
 
 function App() {
-  const { isServerless, experimentalFeatures } = usePluginContext();
+  const { isServerless } = usePluginContext();
 
-  const routes = getRoutes(isServerless, experimentalFeatures);
+  const routes = getRoutes(isServerless);
 
   return (
     <Routes enableExecutionContextTracking={true}>

x-pack/solutions/observability/plugins/slo/public/plugin.ts

@@ -44,7 +44,6 @@ export class SLOPlugin
 {
   private readonly appUpdater$ = new BehaviorSubject<AppUpdater>(() => ({}));
   private experimentalFeatures: ExperimentalFeatures = {
-    management: { enabled: false },
     ruleFormV2: { enabled: false },
   };
 

x-pack/solutions/observability/plugins/slo/public/routes/routes.tsx

@@ -20,12 +20,10 @@ import {
   SLO_SETTINGS_PATH,
 } from '../../common/locators/paths';
 import { SloSettingsPage } from '../pages/slo_settings/slo_settings';
-import { ExperimentalFeatures } from '../../common/config';
 import { SloManagementPage } from '../pages/slo_management/slo_management_page';
 
 export const getRoutes = (
-  isServerless?: boolean,
-  experimentalFeatures?: ExperimentalFeatures
+  isServerless?: boolean
 ): {
   [key: string]: {
     handler: () => React.ReactElement;
@@ -73,17 +71,13 @@ export const getRoutes = (
           },
         }
       : {}),
-    ...(!!experimentalFeatures?.management.enabled
-      ? {
-          [SLOS_MANAGEMENT_PATH]: {
-            handler: () => {
-              return <SloManagementPage />;
-            },
-            params: {},
-            exact: true,
-          },
-        }
-      : {}),
+    [SLOS_MANAGEMENT_PATH]: {
+      handler: () => {
+        return <SloManagementPage />;
+      },
+      params: {},
+      exact: true,
+    },
     [SLO_DETAIL_PATH]: {
       handler: () => {
         return <SloDetailsPage />;