The reorder test helper does not work correctly when a direction is explicitly set

**Describe the bug**
The reorder test helper does not work correctly when a direction is explicitly set.

**To Reproduce**
Steps to reproduce the behavior:

1. Use `{{sortable-group groupName="closableTabs" direction='x' onChange=@onReorder}}` on a List Element2.
2. Use the reorder helper in the test file

**Expected behavior**
The new order of the items in the list is the one provided to the reorder helper.

**Additional context**

#### The Template File
```hbs

{{#each @views as |exploration|}}

1. 
   ...
   ```

   #### Inside the test logic

   ```ts
   import { reorder } from 'ember-sortable/test-support/helpers';

   ...

   await reorder(
   'mouse',
   '[data-test-tabs]',
   `[data-test-id="${explorations[1].explorationId}"]`,
   `[data-test-id="${explorations[0].explorationId}"]`,
   `[data-test-id="${explorations[3].explorationId}"]`,
   `[data-test-id="${explorations[2].explorationId}"]`
   );
   ```

   **Workaround**

   ```ts
   get direction() {
   if (ENV.environment === 'test') {
   return;
   }
   return 'x';
   }
   ```

   ```diff
   + {{sortable-group groupName="closableTabs" direction=this.direction onChange=@onReorder}}
   - {{sortable-group groupName="closableTabs" direction='x' onChange=@onReorder}}
   ```