Backend Alerding SumState: fix periodic onSetSumState doesn't overrid…

…e SumStateSchedule (#2561)

OnSetSumState gets send ~every 5min -> the oldMsg would be constantly updated and therefore would never be send.
This behaviour is fixed by checking if the oldMsg/scheduled message has the same sumState (warning, fault) as the current SumState reported by the Edge.

io.openems.backend.alerting/src/io/openems/backend/alerting/handler/SumStateHandler.java

@@ -144,7 +144,9 @@ protected void addOrUpdate(Edge edge, Level sumState) {
 				this.log.warn(ex.getMessage());
 			}
 		} else {
-			oldMsg.setSumState(sumState, this.timeService.now());
+			if (oldMsg.getSumState() != sumState) {
+				oldMsg.setSumState(sumState, this.timeService.now());
+			}
 			if (!oldMsg.isEmpty()) {
 				this.msgScheduler.schedule(oldMsg);
 			}