[ResponseOps][Cases] Support horizontal scrolling for tables inside the markdown editor (#216979)

Closes https://github.com/elastic/kibana/issues/216421

## Summary

- Applied changes to improve layout stability: removed the `word-break
`and limited the outer flex item to `max-width: 75%`, as suggested in
the ticket


https://github.com/user-attachments/assets/607e9867-e10c-4118-9567-580549708806

---------

Co-authored-by: Christos Nasikas <xristosnasikas@gmail.com>
Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>

x-pack/platform/plugins/shared/cases/public/components/case_view/components/case_view_activity.tsx

@@ -14,6 +14,7 @@ import {
   EuiSpacer,
   EuiScreenReaderOnly,
 } from '@elastic/eui';
+import { css } from '@emotion/react';
 import React, { useCallback, useMemo, useState } from 'react';
 import { isEqual } from 'lodash';
 import { useCasesLocalStorage } from '../../../common/use_cases_local_storage';
@@ -204,7 +205,12 @@ export const CaseViewActivity = ({
 
   return (
     <>
-      <EuiFlexItem grow={6}>
+      <EuiFlexItem
+        grow={6}
+        css={css`
+          max-width: 75%;
+        `}
+      >
         <CaseViewTabs caseData={caseData} activeTab={CASE_VIEW_PAGE_TABS.ACTIVITY} />
         <Description
           isLoadingDescription={isLoadingDescription}

x-pack/platform/plugins/shared/cases/public/components/markdown_editor/scrollable_markdown_renderer.tsx

@@ -15,7 +15,6 @@ import { MarkdownRenderer } from './renderer';
 export const getContentWrapperCss = (euiTheme: EuiThemeComputed<{}>) => css`
   padding: ${`${euiTheme.size.m} ${euiTheme.size.l}`};
   text-overflow: ellipsis;
-  word-break: break-word;
   display: -webkit-box;
   -webkit-box-orient: vertical;
 `;

x-pack/platform/plugins/shared/cases/public/components/user_actions/comment/user.tsx

@@ -96,6 +96,11 @@ export const createUserAttachmentUserActionBuilder = ({
           !isLoading &&
           hasDraftComment(appId, caseId, attachment.id, attachment.comment),
       }),
+      css: css`
+        [class*='euiTimelineItemEvent'] {
+          max-width: 100%;
+        }
+      `,
       children: (
         <>
           <UserActionMarkdown