BF: Handle when record of last open app windows is an invalid value (e.g. from old version)

[TEParsons]

Should fix #6812 (though I was unable to replicate the issue on Windows so please give this a try @aforren1 and let me know if it fixes the problem)

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 50.72%. Comparing base (9911f90) to head (8bec989).
Report is 8 commits behind head on release.

Additional details and impacted files

@@             Coverage Diff             @@
##           release    #6885      +/-   ##
===========================================
+ Coverage    49.63%   50.72%   +1.08%     
===========================================
  Files          332      332              
  Lines        61208    61210       +2     
===========================================
+ Hits         30380    31047     +667     
+ Misses       30828    30163     -665     

Components	Coverage Δ
app	∅ <ø> (∅)
boilerplate	∅ <ø> (∅)
library	∅ <ø> (∅)
vm-safe library	∅ <ø> (∅)

[aforren1]

Thanks @TEParsons, I'll check today or tomorrow.

[aforren1]

Seems to work for me-- I could reproduce on Windows by deleting my existing ...\AppData\Roaming\psychopy3 folder, and trying to launch the psychopy app from a new conda env (e.g. conda create -n test python=3.10 + pip install psychopy + psychopy). The current release briefly shows the splash screen & exits, and this branch lets the app fully launch.

The standalone 2024.2.1 didn't seem affected by this issue (??)