Vshard shows alerts for replica, which are not in the vshard's config

[Serpentian]

The problem here is that, if we connect any kind of replica to our shard, vshard will suppose, that it's part of the current shard, master will throw errors for this replicas:

-- Use example, add replica (let's suppose, this is non anon CDC)
tarantool> box.cfg{replication = {'storage:[email protected]:3301', 'storage:[email protected]:3302'}}

----

-- Now on `replica_1_a` we'll see:
unix/:./data/storage_1_a.control> vshard.storage.info()
<...>
  alerts:
  - ['UNREACHABLE_REPLICA', 'Replica 5891c9d7-a7f4-4fca-b9bc-07246c040141 isn''t active']
  - ['LOW_REDUNDANCY', 'Only one replica is active']

Master should not alert about replicas, which are not in vshard's config.