Remove note on storing metadata on destination cluster

This is not recommended for performance reasons, so we should remove mention of it.

Author: mvankeulen94

README.md

@@ -36,8 +36,6 @@ migration-verifier needs a MongoDB cluster to store its state. This cluster *mus
 
 See [above](#Quick-Start) for a one-line command to start up a local, single-node replica set that you can use for this purpose.
 
-The verifier can alternatively store its metadata on the destination cluster. This can severely degrade performance, though. Also, if you’re using mongosync, it requires either disabling mongosync’s destination write blocking or giving the `bypassWriteBlockingMode` to the verifier’s `--metaURI` user.
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