Once SwitchWrites has been run DropSources cleans up the source resources by deleting the
source tables for a MoveTables workflow or source shards for a Reshard workflow. It also
cleans up other artifacts of the workflow, deleting forward and reverse replication streams and
Warning: This command actually deletes data. We recommend that you run this
with the -dry_run parameter first and reads its output so that you know which actions will be performed.