fix: add missing transformer registrations to data-plane-selector extensions

[ndr-brt]

What this PR changes/adds

Adding missing transformers needed for making the data-plane-selector work as a standalone.
To verify these, the scope of RemoteDataPlaneSelectorServiceTest and DataplaneSelectorControlApiEndToEndTest has been improved

Why it does that

fix bug

Further notes

List other areas of code that have changed but are not necessarily linked to the main feature. This could be method
signature changes, package declarations, bugs that were encountered and were fixed inline, etc.

Linked Issue(s)

Closes #4388

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Codecov Report

Attention: Patch coverage is 87.50000% with 2 lines in your changes missing coverage. Please review.

Project coverage is 74.97%. Comparing base (7f20ba5) to head (61e68b9).
Report is 374 commits behind head on main.

Files	Patch %	Lines
...plane/selector/RemoteDataPlaneSelectorService.java	66.66%	2 Missing ⚠️

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Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4391      +/-   ##
==========================================
+ Coverage   71.74%   74.97%   +3.22%     
==========================================
  Files         919     1071     +152     
  Lines       18457    21481    +3024     
  Branches     1037     1174     +137     
==========================================
+ Hits        13242    16105    +2863     
- Misses       4756     4852      +96     
- Partials      459      524      +65     

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