PathFinder.invalidate_caches should include MetadataPathFinder.invalidate_caches

[jaraco]

MetadataPathFinder.invalidate_caches should be called from PathFinder.invalidate_caches, as that will match the behavior that would happen if MetadataPathFinder were on sys.meta_path.

Originally posted by @jaraco in #116763 (comment)

Linked PRs

• gh-116811: Ensure MetadataPathFinder.invalidate_caches is reachable when delegated through PathFinder. #116812
• [3.12] gh-116811: Ensure MetadataPathFinder.invalidate_caches is reachable when delegated through PathFinder. (GH-116812) #116864
• [3.11] gh-116811: Ensure MetadataPathFinder.invalidate_caches is reachable when delegated through PathFinder. (GH-116812) #116865

[jaraco]

PathFinder already delegates its find_distributions to MetadataPathFinder, so it's probably best to delegate this function as well.

[hugovk]

Closing as the PRs have been merged and backported. Please let us know if there's still more to do. Thanks!