[Backport workspace-pr-integr] Refactor: move workspace logic from repository to saved objects client wrapper

[SuZhou-Joe]

manual backport #248

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 79.54545% with 18 lines in your changes are missing coverage. Please review.

Project coverage is 55.68%. Comparing base (57ee06d) to head (6316a9a).

Files	Patch %	Lines
...ed_objects_wrapper_for_check_workspace_conflict.ts	87.01%	2 Missing and 8 partials ⚠️
...ore/server/saved_objects/service/lib/repository.ts	0.00%	6 Missing ⚠️
...server/saved_objects/import/validate_references.ts	0.00%	1 Missing ⚠️
src/plugins/workspace/server/plugin.ts	66.66%	1 Missing ⚠️

Additional details and impacted files

@@                   Coverage Diff                    @@
##           workspace-pr-integr     #264       +/-   ##
========================================================
- Coverage                66.94%   55.68%   -11.27%     
========================================================
  Files                     3322     3034      -288     
  Lines                    64139    60104     -4035     
  Branches                 10289     9656      -633     
========================================================
- Hits                     42938    33466     -9472     
- Misses                   18687    24627     +5940     
+ Partials                  2514     2011      -503     

Flag	Coverage Δ
_1	31.98% <79.54%> (+0.28%)	⬆️
_2	?
_3	43.45% <0.00%> (+0.05%)	⬆️
_4	35.21% <0.00%> (+0.03%)	⬆️

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.