Fix event ordering for item events (#3628)

Posting the `ItemAddedEvent` after notifying the listeners results in `ItemStateUpdated/ChangedEvents` before the `ItemAddedEvent` because the state could be altered by persistence services. This is at least unexpected and can be fixed by swapping the order.

Signed-off-by: Jan N. Klug <github@klug.nrw>

bundles/org.openhab.core/src/main/java/org/openhab/core/internal/items/ItemRegistryImpl.java

@@ -370,20 +370,20 @@ public Collection<Item> getItemsByTagAndType(String type, String... tags) {
 
     @Override
     protected void notifyListenersAboutAddedElement(Item element) {
-        super.notifyListenersAboutAddedElement(element);
         postEvent(ItemEventFactory.createAddedEvent(element));
+        super.notifyListenersAboutAddedElement(element);
     }
 
     @Override
     protected void notifyListenersAboutRemovedElement(Item element) {
-        super.notifyListenersAboutRemovedElement(element);
         postEvent(ItemEventFactory.createRemovedEvent(element));
+        super.notifyListenersAboutRemovedElement(element);
     }
 
     @Override
     protected void notifyListenersAboutUpdatedElement(Item oldElement, Item element) {
-        super.notifyListenersAboutUpdatedElement(oldElement, element);
         postEvent(ItemEventFactory.createUpdateEvent(element, oldElement));
+        super.notifyListenersAboutUpdatedElement(oldElement, element);
     }
 
     @Override