[Backport 2.17] [Manual Backport 2.x] [Workspace] Add user settings

[opensearch-trigger-bot]

Backport eccf54f from #8057.

[github-actions]

❌ Invalid Changelog Heading

The '## Changelog' heading in your PR description is either missing or malformed. Please make sure that your PR description includes a '## Changelog' heading with proper spelling, capitalization, spacing, and Markdown syntax.

[codecov]

Codecov Report

Attention: Patch coverage is 66.94561% with 79 lines in your changes missing coverage. Please review.

Please upload report for BASE (2.17@0d6c74b). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
src/plugins/workspace/server/utils.ts	5.55%	17 Missing ⚠️
src/core/server/ui_settings/ui_settings_client.ts	77.08%	4 Missing and 7 partials ⚠️
...rkspace/public/components/workspace_list/index.tsx	80.00%	7 Missing and 3 partials ⚠️
src/plugins/advanced_settings/public/plugin.ts	43.75%	8 Missing and 1 partial ⚠️
...d_settings/public/management_app/user_settings.tsx	64.28%	4 Missing and 1 partial ⚠️
src/plugins/workspace/server/routes/index.ts	0.00%	5 Missing ⚠️
...ntent_management/public/components/page_render.tsx	55.55%	2 Missing and 2 partials ⚠️
src/plugins/workspace/public/plugin.ts	50.00%	3 Missing and 1 partial ⚠️
...r/saved_objects/user_ui_settings_client_wrapper.ts	91.42%	1 Missing and 2 partials ⚠️
...ade_saved_config/create_or_upgrade_saved_config.ts	66.66%	1 Missing and 1 partial ⚠️
... and 6 more

Additional details and impacted files

@@           Coverage Diff           @@
##             2.17    #8074   +/-   ##
=======================================
  Coverage        ?   60.67%           
=======================================
  Files           ?     3737           
  Lines           ?    88653           
  Branches        ?    13770           
=======================================
  Hits            ?    53788           
  Misses          ?    31585           
  Partials        ?     3280           

Flag	Coverage Δ
Linux_1	28.77% <34.73%> (?)
Linux_2	56.38% <70.14%> (?)
Linux_3	37.54% <42.95%> (?)
Linux_4	29.73% <8.41%> (?)
Windows_1	28.78% <34.73%> (?)
Windows_2	56.33% <70.14%> (?)
Windows_3	37.54% <42.95%> (?)
Windows_4	29.73% <8.41%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.