Techdebt: Remove warnings

[bblommers]

Cryptography >= 40.0.0 introduces a new property, not_valid_before_utc, that will replace the old not_valid_before-property. This PR supports both properties (and therefore all versions of cryptography).

This PR also:

• updates some CI dependencies
• tests these changes with an older version of cryptography
• improves an EC2 test to reduce the chances that it finds a resources created by other tests.
• fixes some pytest warnings since tests (methods that start with test_) should not return anything

[codecov]

Codecov Report

Attention: 8 lines in your changes are missing coverage. Please review.

Comparison is base (9aef694) 95.88% compared to head (abf59a2) 95.86%.
Report is 23 commits behind head on master.

Files	Patch %	Lines
moto/acm/models.py	71.42%	4 Missing ⚠️
moto/acmpca/models.py	50.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7350      +/-   ##
==========================================
- Coverage   95.88%   95.86%   -0.03%     
==========================================
  Files         843      843              
  Lines       82578    82838     +260     
==========================================
+ Hits        79178    79410     +232     
- Misses       3400     3428      +28     

Flag	Coverage Δ
servertests	32.55% <9.09%> (+0.03%)	⬆️
unittests	95.82% <63.63%> (-0.03%)	⬇️

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[github-actions]

This is now part of moto >= 5.0.2.dev26