perf: pinned python dependency count check

[huniafatima-arbi]

Description:

This PR adds the check to count the number of pinned python dependencies from constraints.tx or common-constraints.txt files. The key is pinned_python_dependencies

Merge checklist:

• Changelog record added
• Documentation updated (not only docstrings)
• Commits are squashed

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 23 lines in your changes missing coverage. Please review.

Project coverage is 73.98%. Comparing base (0971dee) to head (a7a8b64).

Files with missing lines	Patch %	Lines
repo_health/check_pinned_python_dependencies.py	0.00%	22 Missing ⚠️
repo_health/check_ubuntufiles.py	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #509      +/-   ##
==========================================
- Coverage   75.06%   73.98%   -1.08%     
==========================================
  Files          26       27       +1     
  Lines        1512     1534      +22     
==========================================
  Hits         1135     1135              
- Misses        377      399      +22     

Flag	Coverage Δ
unittests	73.98% <0.00%> (-1.08%)	⬇️

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