Replace sklearn.utils.metaestimators.if_delegate_has_method with available_if

[allispaul]

Reference issues/PRs
Fixes #680.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Description
This replaces occurrences of the deprecated sklearn.utils.metaestimators.if_delegate_has_method, which was removed in scikit-learn version 1.3, with sklearn.utils.metaestimators.available_if. Before this change, the pytest tests were throwing errors for me. This is a breaking change because the minimum version of scikit-learn has to be increased from 0.23.1 to 1.1.0.

Screenshots (if appropriate)

Any other comments?
I am still not passing all of the tests, but I think the failing tests are related to other issues.

Checklist

• I have read the guidelines for contributing.
• My code follows the code style of this project. I used flake8 to check my Python changes.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed. I used pytest to check this on Python tests.