Refactor sevennet model

[YutackPark]

Summary

Include a summary of major changes in bullet points:

• Fix 1: torch.dtype == torch.float32 to dtype == torch.float32
• Change 1: raise ValueError if type_map is None. The switch is introduced due to historical reason and should be True.

Checklist

Before a pull request can be merged, the following items must be checked:

• Doc strings have been added in the Google docstring format.
  Run ruff on your code.
• Tests have been added for any new functionality or bug fixes.
• All linting and tests pass.

[orionarcher]

Thanks for the update @YutackPark! Ready to merge?

[YutackPark]

Sure!