[lazerg]

This pull request fixes an issue where where('collection', ...) or whereIn('collection', ...) inside a nested where() / orWhere() closure was silently ignored by the Stache entry query builder.

The builder pulls collection clauses out of the wheres and keeps them in its $collections property, so they decide which collection stores get queried. The closure gets a clone of the builder, so the clause landed on the clone's $collections, which is never read. The nested query ended up with no wheres and was dropped, and entries from every collection came back.

This PR fixes it by marking the nested builder, and turning collection clauses on it into a regular where on the collectionHandle index, the same index the status query already uses for its per-collection clauses. That way and / or inside the closure work like any other column.

Fixes #15560