CognitoIDP: Ensure MFA functions work with non-python SDK's

[bblommers]

Fixes #8238

[codecov]

Codecov Report

Attention: Patch coverage is 92.59259% with 2 lines in your changes missing coverage. Please review.

Project coverage is 94.55%. Comparing base (1ace1db) to head (259ec76).
Report is 15 commits behind head on master.

Files with missing lines	Patch %	Lines
moto/cognitoidp/models.py	91.30%	2 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #8241   +/-   ##
=======================================
  Coverage   94.54%   94.55%           
=======================================
  Files        1158     1158           
  Lines      100089   100147   +58     
=======================================
+ Hits        94629    94692   +63     
+ Misses       5460     5455    -5     

Flag	Coverage Δ
servertests	28.89% <55.55%> (+0.01%)	⬆️
unittests	94.52% <92.59%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.