Ignore protobuf generated files in CAP

[rajan-chari]

Why are these changes needed?

Protobuf is an industry standard format for publishing and receiving messages. CAP uses these messages in the message bus.
protoc generates files that bind the message to python. These files are not meant to be fixed by hand.

pre-commit ruff checks fails on these files.

Related issue number

Closes #2190

Checks

• I've included any doc changes needed for https://microsoft.github.io/autogen/. See https://microsoft.github.io/autogen/docs/Contribute#documentation to build and test documentation locally.
• I've added tests (if relevant) corresponding to the changes introduced in this PR.
• I've made sure all auto checks have passed.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 37.55%. Comparing base (8cb5c14) to head (38c35ea).
Report is 7 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2215      +/-   ##
==========================================
+ Coverage   37.53%   37.55%   +0.02%     
==========================================
  Files          77       77              
  Lines        7710     7719       +9     
  Branches     1655     1657       +2     
==========================================
+ Hits         2894     2899       +5     
- Misses       4573     4574       +1     
- Partials      243      246       +3     

Flag	Coverage Δ
unittests	37.54% <ø> (+0.02%)	⬆️

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