Make Enforcer modality-aware

[mzweilin]

What does this PR do?

This PR makes Enforcer aware of modalities in input, and compatible with existing configs without modality.

Type of change

Please check all relevant options.

• Improvement (non-breaking)
• Bug fix (non-breaking)
• New feature (non-breaking)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Testing

Please describe the tests that you ran to verify your changes. Consider listing any relevant details of your test configuration.

• pytest tests/test_enforcer.py

Before submitting

• The title is self-explanatory and the description concisely explains the PR
• My PR does only one thing, instead of bundling different changes together
• I list all the breaking changes introduced by this pull request
• I have commented my code
• 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
• I have run pre-commit hooks with pre-commit run -a command without errors

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Make sure you had fun coding 🙃

[dxoigmn]

How come this doesn't change the Adversary? Also probably want to test your recursive function

[dxoigmn]

Looks good. Do you know what happens when input or target does not "match" input_adv? If input_adv is a list and input is a dict? Probably best to assert types right after the isinstance checks.

[dxoigmn]

LGTM! I would consider the comment.