Fix #1328: Update ContribEstimator wrapper to work with sklearn 1.6+ tags API

[edschofield]

Starting in scikit-learn 1.6, the type-checking functions is_classifier(), is_regressor(),etc. were changed to use a new tags-based mechanism. Yellowbrick's ContribEstimator did not implement __sklearn_tags__(),so when sklearn called it, the call fell through to ContribEstimator.getattr(). Since third-party estimators (the whole reason ContribEstimator exists) typically don't implement sklearn_tags() either, this raised an AttributeError, causing all four type checks to fail.

This fix adds a __sklearn_tags__() method to ContribEstimator that builds a default Tags object (via BaseEstimator) and replaces the estimator_type field with the value from self._estimator_type when set. This preserves the existing behavior where wrap(est, "classifier") makes the estimator pass is_classifier() checks, while remaining forward-compatible with sklearn's tags infrastructure.

After applying this fix, the tests that @jakevdp reported in #1328 to be failing now pass.

$ pytest . -k test_wrapper --tb=short

...
tests/test_contrib/test_wrapper.py::Third party ContribEstimator wrapper::Check that the contrib wrapper passes through correctly PASSED [  5%]
tests/test_contrib/test_wrapper.py::Third party ContribEstimator wrapper::Assert a correct exception is raised on failed access PASSED [ 10%]
...
tests/test_utils/test_wrapper.py::Test the object Wrapper mixin utility::Ensure wrapper recursion isn't possible PASSED [ 94%]
tests/test_utils/test_wrapper.py::Test the object Wrapper mixin utility::Attribute errors should return a YellowbrickAttributeError PASSED [100%]