ref: fix types in several models

[asottile-sentry]

fixes some errors when BaseManager becomes typechecked

[codecov]

Codecov Report

Attention: Patch coverage is 90.47619% with 2 lines in your changes missing coverage. Please review.

Project coverage is 78.05%. Comparing base (eca152a) to head (08ad6f2).
Report is 21 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #72802      +/-   ##
==========================================
- Coverage   78.05%   78.05%   -0.01%     
==========================================
  Files        6601     6602       +1     
  Lines      294329   294372      +43     
  Branches    50751    50754       +3     
==========================================
+ Hits       229729   229760      +31     
- Misses      58361    58373      +12     
  Partials     6239     6239              

Files	Coverage Δ
src/sentry/models/apitoken.py	95.69% <100.00%> (ø)
src/sentry/models/avatars/base.py	77.77% <100.00%> (+0.20%)	⬆️
src/sentry/models/files/abstractfile.py	91.53% <100.00%> (ø)
src/sentry/models/groupowner.py	95.09% <100.00%> (ø)
src/sentry/models/integrations/integration.py	92.30% <100.00%> (ø)
src/sentry/models/pullrequest.py	100.00% <ø> (ø)
src/sentry/models/team.py	98.31% <100.00%> (-0.03%)	⬇️
src/sentry/models/user.py	90.42% <ø> (ø)
src/sentry/models/userrole.py	98.14% <100.00%> (+0.03%)	⬆️
...ry/notifications/notifications/activity/release.py	90.29% <100.00%> (ø)
... and 2 more

... and 21 files with indirect coverage changes