[Multiple Datasource] Pass selected data sources to plugin consumers when the multi-select component initially loads

[huyaboo]

Description

The multi-selectable component does not call the callback function on initial load of the component. This means that plugins cannot initially fetch the dataSourceIds when first rendering the page. This PR makes a call to the callback function upon componentDidMount()

Issues Resolved

Closes #6324

Screenshot

Screen.Recording.2024-04-03.at.11.29.24.AM.mov

Testing the changes

In the multi-select component, a console.log() statement was added to the callback function and this callback function was passed into the multi-select component. Because the log statement was called without any selection changes, it shows that the callback function was called when the multi-select component initially loaded.

Check List

• All tests pass
  • yarn test:jest
  • yarn test:jest_integration
• New functionality includes testing.
• New functionality has been documented.
• Update CHANGELOG.md
• Commits are signed per the DCO using --signoff

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 67.50%. Comparing base (cf43af3) to head (b9ba13d).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6333   +/-   ##
=======================================
  Coverage   67.49%   67.50%           
=======================================
  Files        3376     3376           
  Lines       65798    65800    +2     
  Branches    10639    10639           
=======================================
+ Hits        44413    44415    +2     
  Misses      18801    18801           
  Partials     2584     2584           

Flag	Coverage Δ
Linux_1	32.60% <ø> (ø)
Linux_2	55.60% <ø> (ø)
Linux_3	44.84% <100.00%> (+<0.01%)	⬆️
Linux_4	35.02% <0.00%> (-0.01%)	⬇️
Windows_1	32.62% <ø> (ø)
Windows_2	55.57% <ø> (ø)
Windows_3	44.85% <100.00%> (+<0.01%)	⬆️
Windows_4	35.02% <0.00%> (-0.01%)	⬇️

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