Fix timing issue in evaluating `cluster-allow-replica-migration` for replicas
There is a timing bug where the primary and replica have different
`cluster-allow-replica-migration` settings. In issue #970, we found that if
the replica receives `CLUSTER SETSLOT` before the gossip update, it remains
in the original shard. This happens because we only process the
`cluster-allow-replica-migration` flag for primaries during `CLUSTER SETSLOT`.
This commit fixes the issue by also evaluating this flag for replicas in the
`CLUSTER SETSLOT` path, ensuring correct replica migration behavior.
Closes#970
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Signed-off-by: Binbin <binloveplay1314@qq.com>
Co-authored-by: Ping Xie <pingxie@outlook.com>
dcc7678fc4