FIX: edge case where module.__file__ is None

[nikostro]

Address edge case where file attribute exists but is None. This was discovered running ARENA on Colab.

This PR contains:

• New features
• Changes to dev-tools e.g. CI config / github tooling
• Docs
• Bug fixes
• Code refactor

What is the current behavior? (You can also link to an open issue here)

• In rare edge cases inregistry.py, a __file__ attribute may exist but be set to None, causing an AttributeError in file = Path(getattr(module, "__file__"))

module = inspect.getmodule(task_type)
assert module
assert not module

What is the new behavior?

Handle this edge case.

Does this PR introduce a breaking change? (What changes might users need to make in their application due to this PR?)

No.

Other information: