TASK: Use setRollbackOnly to ensure nothing is commited during the …

…simulation

solves neos/neos-development-collection#5301 (comment)

src/DoctrineDbalContentGraphProjection.php

@@ -248,9 +248,11 @@ public function inSimulation(\Closure $fn): mixed
             throw new \RuntimeException(sprintf('Invoking %s is not allowed to be invoked recursively. Current transaction nesting %d.', __FUNCTION__, $this->dbal->getTransactionNestingLevel()));
         }
         $this->dbal->beginTransaction();
+        $this->dbal->setRollbackOnly();
         try {
             return $fn();
         } finally {
+            // unsets rollback only flag and allows the connection to work regular again
             $this->dbal->rollBack();
         }
     }