[2.x] ShouldHandleEventsAfterCommit/ShouldDispatchAfterCommit listeners should be executed after nested transaction is commited during tests

### Current Behavior

The tests implemented in https://github.com/flarum/framework/pull/4833 are missing to test the behaviour when the application code creates a transaction in it self (results in a nested transaction).

The fix in https://github.com/flarum/framework/pull/4833 leads to that an event marked with ShouldDispatchAfterCommit is dispatched to early during tests.

### Steps to Reproduce

Extend the AfterCommitListenerTest test case with following code and resolve deps:

```
#[Test]
public function after_commit_event_is_dispatched_after_a_transaction(): void
{
$this->extend(
(new Extend\Event())->listen(AfterCommitDispatchableEvent::class, function () use (&$ran) {
$ran = true;
})
);

$this->connection()->beginTransaction();

$this->app()->getContainer()->make(Dispatcher::class)->dispatch(new AfterCommitDispatchableEvent());

$this->assertFalse(
$ran,
'A ShouldDispatchAfterCommit event should not be dispatched during a nested transaction in a test.'
);

$this->connection()->commit();

$this->assertTrue(
$ran,
'A ShouldDispatchAfterCommit event should be dispatched during an integration test.'
);
}

private function connection(): ConnectionInterface
{
return $this->app()->getContainer()->make(ConnectionInterface::class);
}
```

### Expected Behavior

test should run

### Screenshots

_No response_

### Environment

- Flarum version: 2.0.0-rc.8
- Website URL: http://example.com
- Webserver: [e.g. apache, nginx]
- Hosting environment: [e.g. shared, vps]
- PHP version: x.y.z
- Database: [e.g. MySQL 8.4.11, MariaDB 10.11.2, PostgreSQL 16.1, SQLite 3.45]
- Browser: [e.g. chrome 67, safari 11]

### Output of `php flarum info`

```
Output of "php flarum info", run this in terminal in your Flarum directory.
```

### Possible Solution

_No response_

### Additional Context

_No response_

Start with the AfterCommitListenerTest test case and run the existing after-commit listener tests after resolving dependencies. Exercise the nested transaction scenario using the Dispatcher and ConnectionInterface entry points shown in the issue; done means the event is not dispatched before the nested commit and is dispatched after it.

Written by the indexing model from the issue text.