Stop extending from BindableRuntimeHintsRegistrar

[snicoll]

We have this pattern where we extend BindableRuntimeHintsRegistrar to register binding for a class. It's a bit confusing, the class should implement RuntimeHintsRegistrar and call the public factory method instead

[snicoll]

Closing in favor of PR #44266. Thanks again, @ngocnhan-tran1996.