The support for fromMigrate in the batched deletes (introduced with SERVER-77543) is no longer required.

The idea was to use batched delete in the range deleter, but after some testing we highlighted that this would increase latency causing an impact on the user's workload (see SERVER-66279).

Additionally, this logic assumes the documents will not change during the migration, and it is not necessary to ensure they still match before deleting. There is concern this assumption is not valid, as users can connect directly to the shard.