$indexStats may read at a point in time where it observes an index completed in the CollectionIndexUsageTracker (in-memory), but whose durable catalog information is not visible in the current snapshot.

As of SERVER-47866, $indexStats needs to consider each index's visibility, because it is no longer protected from AutoGetCollectionForRead.

I see a few options:

• Don't report indexes that have a minimumVisibleSnapshot higher than the current read timestamp. Since we setMinimumVisibleSnapshot at the begin and end of an index build, this would fail to report just-completed indexes that otherwise should be seen as in-progress.
• Create a helpers IndexCatalogEntry::isPresentInMySnapshot() and IndexCatalogEntry::isReadyInMySnapshot() that are renamed from the existing _catalogIsPresent and _catalogIsReady functions. This should allow us to preserve the same behavior and without relying on minimumVisibleSnapshot

Note: the reason why the current isReady() check is not sufficient is because of this debug check which does not fail, but will trigger a different invariant in the DurableCatalog::isIndexReady.