heal: Fix periodic healing cleanup (#10569)

isEnded() was incorrectly calculating if the current healing sequence is
ended or not. h.currentStatus.Items could be empty if healing is very
slow and mc admin heal consumed all items.

cmd/admin-heal-ops.go

@@ -528,7 +528,7 @@ func (h *healSequence) hasEnded() bool {
 	if h.clientToken == bgHealingUUID {
 		return false
 	}
-	return len(h.currentStatus.Items) == 0 || h.currentStatus.Summary == healStoppedStatus || h.currentStatus.Summary == healFinishedStatus
+	return !h.endTime.IsZero()
 }
 
 // stops the heal sequence - safe to call multiple times.