Fix repeating close dialog on macOS and qt 5.12

[Czaki]

Description

Try to solve (from @tlambert03)

if you press cmd-q, and then press it again (as the dialog instructs), it doesn't quit... it just opens more dialogs

Untitled.mov

Type of change

• Bug-fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

References

closes #5335

How has this been tested?

• example: the test suite for my feature covers cases x, y, and z
• example: all tests pass with my change
• example: I check if my changes works with both PySide and PyQt backends
  as there are small differences between the two Qt bindings.

Final checklist:

• My PR is the minimum possible work for the desired functionality
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• If I included new strings, I have used trans. to make them localizable.
  For more information see our translations guide.

[codecov]

Codecov Report

Merging #5337 (f42d49e) into main (aaea9f0) will increase coverage by 0.00%.
The diff coverage is 20.00%.

@@           Coverage Diff           @@
##             main    #5337   +/-   ##
=======================================
  Coverage   89.08%   89.08%           
=======================================
  Files         582      582           
  Lines       49313    49318    +5     
=======================================
+ Hits        43931    43936    +5     
  Misses       5382     5382           

Impacted Files	Coverage Δ
napari/_qt/qt_main_window.py	76.04% <20.00%> (-0.52%)	⬇️
napari/utils/theme.py	89.79% <0.00%> (+0.68%)	⬆️
napari/utils/info.py	83.33% <0.00%> (+1.11%)	⬆️
napari/_qt/__init__.py	55.17% <0.00%> (+6.89%)	⬆️

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[psobolewskiPhD]

I can't say I get the code, but it does fix the issue in my macOS 12.6 Rosetta-emulated x86 env with pyqt 5.12.3.
👍 @Czaki

[Czaki]

I add comments with explanations.

[psobolewskiPhD]

OK, I think I see it now. I was writting a question and explained it to myself.
My hangup was that quit_app is actually a bool so either False or True so it works with the dict you defined at the beginning in L118.
I'd still rather someone else review this just to be safe,

[Czaki]

I could change bool to enum to increase readability if needed.

[psobolewskiPhD]

No no, it's me being an imbecile and not comprehending: self._is_close_dialog[quit_app]

[tlambert03]

nice job @Czaki :) (can confirm this fixes it on 5.12 for me)

[Czaki]

Would you vote for 0.4.18 bugfix release or could it wait until 0.5.0?

[tlambert03]

don't have an opinion

[Czaki]

Ok. Will merge after 24h.