fix: Also remove digits at the start and underscore on both ends of a…

…ppid

Co-authored-by: Ferdinand Thiessen <[email protected]>
Signed-off-by: Côme Chilliet <[email protected]>

lib/private/App/AppManager.php

@@ -956,6 +956,6 @@ public function isBackendRequired(string $backend): bool {
 	 */
 	public function cleanAppId(string $app): string {
 		/* Only lowercase alphanumeric is allowed */
-		return preg_replace('/[^a-z0-9_]+/', '', $app);
+		return preg_replace('/(^[0-9_]|[^a-z0-9_]+|_$)/', '', $app);
 	}
 }