fix(group): Set the display name on every backends that supports it

Otherwise it apply the change only to the group backend with
ISetDisplaynameBackend

Signed-off-by: Carl Schwan <carl@carlschwan.eu>

lib/private/Group/Group.php

@@ -79,6 +79,7 @@ class Group implements IGroup {
 	#[\Override]
 	public function setDisplayName(string $displayName): bool {
 		$displayName = trim($displayName);
+		$changed = false;
 		if ($displayName !== '') {
 			$this->dispatcher->dispatchTyped(new BeforeGroupChangedEvent($this, 'displayName', $displayName, $this->displayName));
 			$oldDisplayName = $this->displayName;
@@ -86,11 +87,14 @@ class Group implements IGroup {
 				if (($backend instanceof ISetDisplayNameBackend)
 					&& $backend->setDisplayName($this->gid, $displayName)) {
 					$this->displayName = $displayName;
-					$this->dispatcher->dispatchTyped(new GroupChangedEvent($this, 'displayName', $displayName, $oldDisplayName));
-					return true;
+					$changed = true;
 				}
 			}
 		}
+		if ($changed) {
+			$this->dispatcher->dispatchTyped(new GroupChangedEvent($this, 'displayName', $displayName, $oldDisplayName));
+			return true;
+		}
 		return false;
 	}