Add function to selectively remove estimators from the registry

[mgxd]

What would you like to see added in this software?

This has come up in nipreps/fmriprep#3060

To avoid filtering out estimators multiple times, we should incorporate a selective purge in the same spirit as

sdcflows/sdcflows/fieldmaps.py

Lines 493 to 496 in 375dd7a

	def clear_registry():
	"""Empty registries."""
	_estimators.clear()
	_intents.clear()

to avoid accessing private _estimators.

Do you have any interest in helping implement the feature?

Yes

Additional information / screenshots

No response