Enable no_implicit_optional globally [mypy]

[cdce8p]

Proposed change

Mypy will soon make no_implicit_optional the default behavior. Currently, it's only applied together with strict typing. This PR enables it globally.

def f(
-    var: int = None
+    var: int | None = None
) -> None:
    ...

See:
python/mypy#9091
python/mypy#13401

Depends on:

• Fix implicit Optional [core] #76719
• Fix implicit Optional [a-n] #76720
• Fix implicit Optional [p-s] #76721
• Fix implicit Optional [t-z] #76722

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Deprecation (breaking change to happen in the future)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
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• Tests have been added to verify that the new code works.

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[epenet]

LGTM