fix: Update display name in User object

This is breaking other consumers of the user object as they will use the old display name. This was an issue in Talk where they cache the display names.

Signed-off-by: Louis Chmn <louis@chmn.me>

Author: artonge

lib/UserBackend.php

@@ -542,6 +542,7 @@ public function updateAttributes(string $uid): void {
 			if ($newDisplayname !== null
 				&& $currentDisplayname !== $newDisplayname) {
 				$this->setDisplayName($uid, $newDisplayname);
+				$user->setDisplayName($newDisplayname);
 				$this->logger->debug('Display name updated', ['app' => 'user_saml', 'user' => $user->getUID()]);
 				$this->eventDispatcher->dispatchTyped(new UserChangedEvent($user, 'displayName', $newDisplayname, $currentDisplayname));
 				$this->logger->debug('Display name update event dispatched', ['app' => 'user_saml', 'user' => $user->getUID()]);