fix(webhook_listeners): Allow null for user_id_filter for oracle

Empty string and null are the same thing on oracle databases so we have
 to allow it.

Signed-off-by: Côme Chilliet <come.chilliet@nextcloud.com>

apps/webhook_listeners/lib/Db/WebhookListener.php

@@ -60,8 +60,9 @@ class WebhookListener extends Entity implements \JsonSerializable {
 	protected $eventFilter;
 
 	/**
-	 * @var string
+	 * @var ?string
 	 * If not empty, id of the user that needs to be connected for the webhook to trigger
+	 * @psalm-suppress PropertyNotSetInConstructor
 	 */
 	protected $userIdFilter;
 

apps/webhook_listeners/lib/Db/WebhookListenerMapper.php

@@ -233,7 +233,7 @@ class WebhookListenerMapper extends QBMapper {
 		return $this->findEntities($qb);
 	}
 
-	private function buildCacheKey(?string $userIdFilter = ''): string {
+	private function buildCacheKey(?string $userIdFilter): string {
 		return self::EVENTS_CACHE_KEY_PREFIX.'_'.($userIdFilter ?? '');
 	}
 }

apps/webhook_listeners/lib/Migration/Version1000Date20240527153425.php

@@ -54,7 +54,7 @@ class Version1000Date20240527153425 extends SimpleMigrationStep {
 				'notnull' => false,
 			]);
 			$table->addColumn('user_id_filter', Types::STRING, [
-				'notnull' => true,
+				'notnull' => false,
 				'length' => 64,
 			]);
 			$table->addColumn('headers', Types::TEXT, [