Add extension mechanism for class mapping decorators

[gayathrir11]

Summary

This PR improvises the extension mechanism for class mapping in form mode. It also fixes the issue where we are unable to open the runtime associated with ServiceStore mapping in form mode.

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[changeset-bot]

🦋 Changeset detected

Latest commit: bd06075

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 13 packages

Name	Type
@finos/legend-studio	Minor
@finos/legend-extension-external-store-service	Patch
@finos/legend-manual-tests	Patch
@finos/legend-extension-dsl-serializer	Patch
@finos/legend-extension-dsl-data-space	Patch
@finos/legend-extension-dsl-diagram	Patch
@finos/legend-extension-dsl-text	Patch
@finos/legend-studio-app	Patch
@finos/legend-studio-extension-management-toolkit	Patch
@finos/legend-studio-extension-query-builder	Patch
@finos/legend-query-app	Patch
@finos/legend-studio-deployment	Patch
@finos/legend-query-deployment	Patch

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[codecov]

Codecov Report

Merging #654 (bd06075) into master (729e248) will decrease coverage by 0.26%.
The diff coverage is 21.56%.

@@            Coverage Diff             @@
##           master     #654      +/-   ##
==========================================
- Coverage   43.88%   43.61%   -0.27%     
==========================================
  Files         898      904       +6     
  Lines       39995    40328     +333     
  Branches     9189     9243      +54     
==========================================
+ Hits        17551    17591      +40     
- Misses      22380    22673     +293     
  Partials       64       64              

Impacted Files	Coverage Δ
...c/components/studio/DSLSerializer_StudioPlugin.tsx	20.79% <0.00%> (ø)
...mapping-editor/InstanceSetImplementationEditor.tsx	15.72% <0.00%> (-1.28%)	⬇️
...r/InstanceSetImplementationSourceSelectorModal.tsx	21.31% <0.00%> (-5.11%)	⬇️
...t-panel/mapping-editor/MappingExecutionBuilder.tsx	12.02% <0.00%> (ø)
...itor/edit-panel/mapping-editor/MappingExplorer.tsx	46.75% <0.00%> (-0.62%)	⬇️
...or/edit-panel/mapping-editor/MappingTestEditor.tsx	11.29% <0.00%> (ø)
...apping-editor/OperationSetImplementationEditor.tsx	10.52% <ø> (ø)
...kages/legend-studio/src/stores/NewElementState.tsx	40.74% <ø> (ø)
.../mapping/FlatDataInstanceSetImplementationState.ts	10.60% <ø> (ø)
...ment-editor-state/mapping/MappingExecutionState.ts	7.90% <0.00%> (ø)
... and 29 more

[akphi]

@gayathrir11 I took the liberty to update the title to be more narrow. Also, I left some minor comments, other than that, LGTM!