Ignore deprecated files from mypy test

[jackgerrits]

Why are these changes needed?

Related issue number

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• 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 36.90%. Comparing base (5b57271) to head (8cbd09f).
Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2103      +/-   ##
==========================================
+ Coverage   36.88%   36.90%   +0.01%     
==========================================
  Files          68       68              
  Lines        7062     7061       -1     
  Branches     1540     1541       +1     
==========================================
+ Hits         2605     2606       +1     
+ Misses       4228     4225       -3     
- Partials      229      230       +1     

Flag	Coverage Δ
unittests	36.90% <ø> (+0.01%)	⬆️

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