When a replica operates in the critical disk utilization mode, all
incoming migrations are being rejected by rejecting an incoming
sstable file.
In the topology_coordinator, the rejected tablet is moved into the
cleanup_target state in order to revert migration. Otherwise, retry
happens and a cluster stays in the tablet_migration transition state
preventing any other topology changes to happen, e.g. scaling out.
Once the tablet migration is rejected, the load balancer will schedule
a new migration.
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