getMores are not denied like other read commands https://github.com/mongodb/mongo/blob/d0a7b4e6b3c4ae2d356ce23996ecf3f7ed56ad9b/src/mongo/db/repl/tenant_migration_donor_access_blocker.cpp#L58
in fact we also have tests to ensure getMores aren't rejected after a commit https://github.com/mongodb/mongo/blob/a9684a6176388f095a6a2b7857c042a89bf56530/jstests/serverless/shard_split_read_your_own_writes.js#L56

this is an issue because if the collections are dropped getMores might be rejected with cursorKilled (nonResumable) instead of TennantMigrationCommitted (resumable)