Fix typing errors due to keyring and cv externals changes.

[jwodder]

No description provided.

[yarikoptic]

is that due to changes in types in those involved (keyring, cv?) libraries i.e. could fail if used with older libs?

[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: -0.01% ⚠️

Comparison is base (71bd0fe) 88.82% compared to head (5a10ab9) 88.81%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1316      +/-   ##
==========================================
- Coverage   88.82%   88.81%   -0.01%     
==========================================
  Files          76       76              
  Lines       10191    10192       +1     
==========================================
  Hits         9052     9052              
- Misses       1139     1140       +1     

Flag	Coverage Δ
unittests	88.81% <100.00%> (-0.01%)	⬇️

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Files Changed	Coverage Δ
dandi/tests/fixtures.py	97.52% <ø> (ø)
dandi/keyring.py	88.88% <100.00%> (+0.20%)	⬆️

... and 1 file with indirect coverage changes

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[jwodder]

@yarikoptic

• The keyring-related typing errors were due to changes in mypy and/or keyring (I'm not going to try to figure out which). I don't believe keyring changed in any way that affects the functioning of dandi.
• I believe the cv2 typing errors occurred because the library (which is written in C++) only recently added Python type annotations, and these annotations describe interfaces that are stricter than what actually works (e.g., apiPreference is declared as an int, but the tests still succeed when a None is passed instead). This PR updates the code to use cv2 the way its annotations say it should be used.

[yarikoptic]

coolio, I will then merge this one whenever turns green and then #1315 to release. Thank you!

[github-actions]

🚀 PR was released in 0.56.0 🚀