Fix deletion of Mirrors with --range-key option

[raminqaf]

Currently, the deletion of Mirrors having the --range-key option set doesn't work correctly. During the clean-up job, we need the schema from the topic registry to build the topology. However, we are deleting the topic along with the schema from the topic registry before running the clean-up job.
The solution would be to move the deletion of the topic from the topic registry after the cleanup job is done.