GitHub CI job to verify tags are on expected branches

[justsmth]

Description of changes:

• Verify that tags matching specific patterns appear on the expected branches.

Call-outs:

N/A

Testing:

• Script succeeds locally (if I change REMOTE_NAME to "upstream").
• Successful CI run here: https://github.com/aws/aws-lc/actions/runs/13159309149/job/36723792502?pr=2170#step:4:12

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license and the ISC license.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 78.97%. Comparing base (cc9c9f0) to head (e41768a).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2170      +/-   ##
==========================================
- Coverage   78.97%   78.97%   -0.01%     
==========================================
  Files         611      611              
  Lines      105552   105632      +80     
  Branches    14950    14951       +1     
==========================================
+ Hits        83361    83420      +59     
- Misses      21538    21560      +22     
+ Partials      653      652       -1     

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