Remove funtracks deprecation warnings and TracksController

[TeunHuijben]

Ongoing work to make motile_tracker compatible with funtracks v2(-dev).

This PR focuses on:

• removing any deprecation warnings
• removing TracksController

[codecov-commenter]

Codecov Report

❌ Patch coverage is 92.15686% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 87.13%. Comparing base (562e35e) to head (e5f83f9).

Files with missing lines	Patch %	Lines
src/motile_tracker/motile/backend/solve.py	42.85%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #330      +/-   ##
==========================================
+ Coverage   86.35%   87.13%   +0.78%     
==========================================
  Files          51       52       +1     
  Lines        4244     4245       +1     
==========================================
+ Hits         3665     3699      +34     
+ Misses        579      546      -33     

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[TeunHuijben]

All deprecation warnings are gone, and tracks_controller is completely removed from motile_tracker.

Excusez-moi, for adding tests in this PR, instead of making a new one.

What remains to be done:

• TrackPoints._update_data used UserAddNod, but this function needs the new_node_id. Previously, we used Trackscontroller._get_new_node_ids, but we lost the TracksController. Solutions: 1) host _get_new_node_ids somewhere in Tracks (can be accelerated using tracksdata, later), or 2) stick to current while look (bad)
• After merging two PRs in funtracks, we can replace the funtracks pin in pyproject

[TeunHuijben]

Ready for review! But we should only merge after Funtracks PRs 155 and 156 are merged (so I can replace the git commit pin in pyproject by an actual version)