test(hydra): isolate Issue7953 fixture table to fix behat collision

| Q             | A
| ------------- | ---
| Branch?       | 4.3
| Tickets       | refs #7953
| License       | MIT
| Doc PR        | ∅

Entity\Dummy and Entity\Issue7953\Dummy both auto-derive table name
"Dummy", so SchemaTool::createSchema throws TableAlreadyExists and
cascades 500s through every later behat scenario.

Author: soyuka

tests/Fixtures/TestBundle/Entity/Issue7953/Dummy.php

@@ -40,6 +40,7 @@
     ],
 )]
 #[ORM\Entity]
+#[ORM\Table(name: 'issue7953_dummy')]
 class Dummy
 {
     #[ORM\Id]