Add shape check to MultiDiscrete __eq__ (#1044)

[DenBuzz]

Description

The __eq__ method in the MultiDiscrete space needs to also check the shape of nvec before the equivalence check. If the shapes are not the same, numpy will throw a ValueError saying operands could not be broadcast together.

The fix here is to simply include a check of the shape before the nvec equivalence check.

Fixes #1044

I included a handful of tests for checking if MultiDiscrete spaces are equivalent or not. Including a test with different shaped nvecs that would have errored before these changes.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• I have run the pre-commit checks with pre-commit run --all-files (see CONTRIBUTING.md instructions to set it up)
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[pseudo-rnd-thoughts]

Thanks for the PR looks good