Add MusicFM Support & Fix Bug in mc_musiccaps

[juhayna-zh]

What does this PR do?

Add MusicFM encoder support and fix bug in mc_musiccaps configuration.

1. Upload the code for MusicFM model to enable the MusicFM music encoder to be supported.
2. Fix the configuration bug in mc_musiccaps, which is caused by accidentally renaming directory in f3e6b57

Feature/Issue validation/testing

Please describe the tests that you ran to verify your changes and relevant result summary. Provide instructions so it can be reproduced.
Please also list any relevant details for your test configuration.

• Training & Inference in mc_musiccaps recipe.
  These tests can be replicated by running the scripts provided in examples/mc_musiccaps/scripts/ directory.

Before submitting

• This PR fixes a typo or improves the docs (you can dismiss the other checks if that's the case).
• Did you read the contributor guideline,
  Pull Request section?
• Was this discussed/approved via a Github issue? Please add a link
  to it if that's the case.
• Did you make sure to update the documentation with your changes?
• Did you write any new necessary tests?

Thanks for contributing 🎉!