TASK: Move transactional logic _on_ projection as it does not belong …

…to the subscription store

... which technically only coincidentally uses the same connection and dbal instance

see neos/neos-development-collection#5321 (comment)

Classes/Factory/SubscriptionStore/DoctrineSubscriptionStore.php

@@ -169,19 +169,4 @@ public function transactional(\Closure $closure): mixed
     {
         return $this->dbal->transactional($closure);
     }
-
-    public function createSavepoint(): void
-    {
-        $this->dbal->createSavepoint('SUBSCRIBER');
-    }
-
-    public function releaseSavepoint(): void
-    {
-        $this->dbal->releaseSavepoint('SUBSCRIBER');
-    }
-
-    public function rollbackSavepoint(): void
-    {
-        $this->dbal->rollbackSavepoint('SUBSCRIBER');
-    }
 }