ci: PLT-536: rework migration script to use pg_try_advisory_xact_lock

[farioas]

Switch to pg_try_advisory_xact_lock for locked_migrations

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[codecov]

Codecov Report

Attention: Patch coverage is 0% with 30 lines in your changes missing coverage. Please review.

Project coverage is 76.64%. Comparing base (656fdfd) to head (9959040).
Report is 3 commits behind head on develop.

Files with missing lines	Patch %	Lines
..._studio/core/management/commands/locked_migrate.py	0.00%	30 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #6585      +/-   ##
===========================================
- Coverage    76.73%   76.64%   -0.09%     
===========================================
  Files          169      169              
  Lines        13819    13835      +16     
===========================================
  Hits         10604    10604              
- Misses        3215     3231      +16     

Flag	Coverage Δ
pytests	76.64% <0.00%> (-0.09%)	⬇️

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[jombooth]

LGTM, please update the description to describe the solution in greater detail and correct the pg lock function used (should be pg_try_advisory_xact_lock)