[10.x] Fix mapped renderable exception handling

[xalaida]

In my previous PR #47201, I tries to fix the handling of mapped exceptions with a render hook. The PR was reverted due to a significant mistake I made by moving the mapException method together with prepareException, which I should not have touched. As it was reported by RobertBoes that change breaks exception rendering on the extended internal exceptions. I sincerely apologize for that.

In this PR I have fixed issue from #47201 and also added a missing test for renderable exceptions.

---

Let me describe the progrem again. When we have a custom exception that defines report and render hooks, only the report hook works while the render hook is never called. For instance:

class Handler extends ExceptionHandler
{
    public function register(): void
    {
        $this->map(RuntimeException::class, AppException::class);
    }
}

class AppException extends Exception
{
    public function report()
    {
        app('sentry')->report($this->getPrevious());
    }

    public function render()
    {
        return new JsonResponse(['message' => 'Something went wrong.']);
    }
}

throw new RuntimeException;

// 👌 The `report` method is called.

// ❌ The `render` method is ignored.

With this change both methods report and render will map the exception at the beginning and handle it correctly:

class Handler
{
    public function report(Throwable $e)
    {
        $e = $this->mapException($e);

        // ...
    }

    public function render($request, Throwable $e)
    {
        $e = $this->mapException($e);

        // ...
    }
}

[taylorotwell]

Tests fail.

[xalaida]

@taylorotwell sorry. Now should be fine.