Alerting: rule evaluation loop's update channel to provide version (#52170)

* handler for update message in rule evaluation routine ignores the message if its version greater or equal.
* replace messages to update the channel if it is not empty

pkg/services/ngalert/api/api_ruler.go

@@ -425,7 +425,7 @@ func (srv RulerSrv) updateAlertRulesInGroup(c *models.ReqContext, groupKey ngmod
 		srv.scheduleService.UpdateAlertRule(ngmodels.AlertRuleKey{
 			OrgID: c.SignedInUser.OrgId,
 			UID:   rule.Existing.UID,
-		})
+		}, rule.Existing.Version+1)
 	}
 
 	for _, rule := range finalChanges.Delete {