GHA: Workaround for macos segfaults

[dweindl]

Homebrew serves swig 4.3.0 which is incompatible with filterwarnings = error in pytest resulting in segfaults (#2565, swig/swig#3061).
For now, the easiest workaround seems to be just ignoring any warnings during macos runs.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.71%. Comparing base (ff6b3f1) to head (7b353a4).
Report is 1 commits behind head on develop.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #2572      +/-   ##
===========================================
- Coverage    77.75%   77.71%   -0.05%     
===========================================
  Files          325      325              
  Lines        21857    21857              
  Branches      1473     1473              
===========================================
- Hits         16996    16986      -10     
- Misses        4834     4844      +10     
  Partials        27       27              

Flag	Coverage Δ
cpp	73.58% <ø> (-0.05%)	⬇️
cpp_python	34.20% <ø> (ø)
petab	37.07% <ø> (ø)
python	72.36% <ø> (-0.05%)	⬇️

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see 1 file with indirect coverage changes

[dweindl]

For now, the easiest workaround seems to be just ignoring any warnings during macos runs.

If this does not get fixed soon, we need to modify the swig-generated cpp files (base + model) to undefine SWIG_HEAPTYPES.