refactor: OPTIC-1621: Remove Stale Feature Flag - fflag_perf_back_lsdv_4695_update_prediction_query_to_use_direct_project_relation

[luarmr]

Removing stale feature flag

fflag_perf_back_lsdv_4695_update_prediction_query_to_use_direct_project_relation -> True

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[codecov]

Codecov Report

Attention: Patch coverage is 83.33333% with 1 line in your changes missing coverage. Please review.

Project coverage is 76.93%. Comparing base (6ecd15e) to head (347194f).
Report is 10 commits behind head on develop.

Files with missing lines	Patch %	Lines
label_studio/projects/models.py	50.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #7002      +/-   ##
===========================================
+ Coverage    76.90%   76.93%   +0.03%     
===========================================
  Files          175      175              
  Lines        14166    14154      -12     
===========================================
- Hits         10894    10890       -4     
+ Misses        3272     3264       -8     

Flag	Coverage Δ
pytests	76.93% <83.33%> (+0.03%)	⬆️

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