feat: data-plane self unregistration

[ndr-brt]

What this PR changes/adds

Make the data plane "unregister" itself instead of "delete".

Why it does that

Briefly state why the change was necessary.

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 #4238

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[codecov-commenter]

Codecov Report

Attention: Patch coverage is 86.66667% with 2 lines in your changes missing coverage. Please review.

Project coverage is 75.03%. Comparing base (7f20ba5) to head (08dcbf6).
Report is 295 commits behind head on main.

Files	Patch %	Lines
...plane/selector/spi/instance/DataPlaneInstance.java	0.00%	2 Missing ⚠️

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Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4249      +/-   ##
==========================================
+ Coverage   71.74%   75.03%   +3.28%     
==========================================
  Files         919     1046     +127     
  Lines       18457    20980    +2523     
  Branches     1037     1169     +132     
==========================================
+ Hits        13242    15742    +2500     
+ Misses       4756     4726      -30     
- Partials      459      512      +53     

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