Use extendedPlugins in integrationTest framework for sample resource plugin testing

[cwperks]

Description

This PR takes advantage of the changes in opensearch-project/OpenSearch#16908 to setup the integrationTests in the sample-resource-plugin using extendedPlugins instead of the workaround that was introduced.

This PR also does a little refactoring on the share flow to modify sharing info of a resource in memory instead of painless which was failing for me locally in testing.

• Category (Enhancement, New feature, Bug fix, Test fix, Refactoring, Maintenance, Documentation)

Refactoring

Check List

• New functionality includes testing
• New functionality has been documented
• New Roles/Permissions have a corresponding security dashboards plugin PR
• API changes companion pull request created
• Commits are signed per the DCO using --signoff

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[codecov]

Codecov Report

Attention: Patch coverage is 68.42105% with 12 lines in your changes missing coverage. Please review.

Project coverage is 72.01%. Comparing base (5bc2523) to head (eb361cd).
Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...y/spi/resources/sharing/SharedWithActionGroup.java	0.00%	7 Missing ⚠️
...ecurity/spi/resources/sharing/ResourceSharing.java	62.50%	2 Missing and 1 partial ⚠️
...ecurity/resources/ResourceSharingIndexHandler.java	90.47%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5322      +/-   ##
==========================================
+ Coverage   71.76%   72.01%   +0.25%     
==========================================
  Files         384      384              
  Lines       23882    23905      +23     
  Branches     3648     3651       +3     
==========================================
+ Hits        17139    17216      +77     
+ Misses       4912     4855      -57     
- Partials     1831     1834       +3     

Files with missing lines	Coverage Δ
...arch/security/spi/resources/sharing/ShareWith.java	66.66% <100.00%> (+2.66%)	⬆️
...ecurity/resources/ResourceSharingIndexHandler.java	65.98% <90.47%> (+8.00%)	⬆️
...ecurity/spi/resources/sharing/ResourceSharing.java	57.14% <62.50%> (+6.54%)	⬆️
...y/spi/resources/sharing/SharedWithActionGroup.java	57.37% <0.00%> (-7.44%)	⬇️

... and 14 files with indirect coverage changes

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