[ENH] allow passing default attr to dask worker profiles

[viniciusdc]

Reference Issues or PRs

closes #3087

What does this implement/fix?

Put a x in the boxes that apply

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds a feature)
• Breaking change (fix or feature that would cause existing features not to work as expected)
• Documentation Update
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Build related changes
• Other (please describe):

Documentation

• For new features or enhancements, a corresponding PR has been opened in the documentation repository (if applicable)
  • Link to docs PR:

Testing

• Did you test the pull request locally?
• Did you add new tests?

How to test this PR?

• Deploy a nebari cluster from this branch
• From within a jupyterlab instance running for a test user with appropriate dask access (give developer to the user under keycloak)
• Deploy e dask-gateway cluster, and under the profiles attest that the default profiles for the worker matches the one specifed in the yaml

Any other comments?