config: remove "to be removed before release" notice mc sstable config
config: remove "to be removed before release" notice mc sstable config

The "enable_sstables_mc_format" config item help text wants to remove itself
before release. Since scylla-3.0 did not get enough mc format mileage, we
decided to leave it in, so the notice should be removed.

Fixes #4003.
Message-Id: <0b545e89c4b4aafcb50646830396549f7b9b8df0@scylladb.com>

avikivity/scylla,avikivity/scylla,scylladb/scylla,avikivity/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla