fix(external_storage): Cast id to int

follow up to #49218

Signed-off-by: Marcel Klehr <mklehr@gmx.net>

[skip ci]

apps/files_external/lib/Controller/UserStoragesController.php

@@ -233,7 +233,7 @@ public function update(
 	 */
 	#[NoAdminRequired]
 	#[PasswordConfirmationRequired]
-	public function destroy($id) {
+	public function destroy(int $id) {
 		return parent::destroy($id);
 	}
 }