[Feature Request] Enable type annotation checker

[XuehaiPan]

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Motivation

I found many wrong type annotations in the codebase after a quick glance.

https://github.com/OmniSafeAI/safety-gymnasium/blob/c1c598ea45f23535405f9941695800bae41d3a4a/safety_gymnasium/utils/random_generator.py#L170-L173

-def constrain_placement(self, placement: dict, keepout: float) -> tuple[float]:
+def constrain_placement(self, placement: list[float], keepout: float) -> tuple[float, float, float, float]:

Also, mypy reports:

-Found 129 errors in 13 files (checked 82 source files)

We should enable a CI workflow to check type annotations are correct.

Solution

Update type annotations and enable mypy in the CI workflow. And remove:

https://github.com/OmniSafeAI/safety-gymnasium/blob/c1c598ea45f23535405f9941695800bae41d3a4a/pyproject.toml#L150-L156

Alternatives

No response

Additional context

No response