feat(RELEASE-2480): add collect_registry_token_secret python script

[happybhati]

This commit adds a python script to replicate the inline bash in the
collect-registry-token-secret managed task in the catalog repo. The task
will be updated to use this python module instead.

• collect_registry_token_secret.py: read data JSON, detect public repos,
  return registry secret name (or empty) via Tekton result
• test_collect_registry_token_secret.py: 11 pytest cases

Assisted-by: Cursor

[codecov-commenter]

Codecov Report

❌ Patch coverage is 97.67442% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 95.64%. Comparing base (62d5b7a) to head (4ae8360).
⚠️ Report is 10 commits behind head on main.

Files with missing lines	Patch %	Lines
...hon/tasks/managed/collect_registry_token_secret.py	97.67%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #860      +/-   ##
==========================================
+ Coverage   95.46%   95.64%   +0.18%     
==========================================
  Files          65       72       +7     
  Lines        6441     7121     +680     
==========================================
+ Hits         6149     6811     +662     
- Misses        292      310      +18     

Flag	Coverage Δ
unit-tests	95.64% <97.67%> (+0.18%)	⬆️

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Files with missing lines	Coverage Δ
...hon/tasks/managed/collect_registry_token_secret.py	97.67% <97.67%> (ø)

... and 11 files with indirect coverage changes

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[happybhati]

/retest