Unraid's mdResyncAction field can retain its last value (e.g. "check")
after a parity check is canceled, causing Pulse to report a stale sync
action indefinitely. The mdResync/mdResyncPos field is the authoritative
indicator: it drops to 0 when no resync is running. Gate SyncAction on
a non-zero position so the alert clears once the sync actually stops.
Refs #1485
rcourtman