TASK: Remove use of save-points for projections

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

the save-point will only be used for REAL projection errors now and never rolled back if catchup errors occur.

With that change in code the save-points are less important because a real projection error should better be thrown at the start before any statements, and even if some statements were issued and a full rollback is done its unlikely that a reactivateSubscription helps that case.

Instead, to repair projections you should replay

Classes/Factory/SubscriptionStore/DoctrineSubscriptionStore.php

@@ -171,19 +171,4 @@ 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');
-    }
 }