Add toggle to show/hide disabled menu items

Few notes:

1. I think the placement of the ‘hide disabled’ button should be Inside the table under the ‘Enabled’ heading. That’s how I implemented it.
2. There’s a corner case, If a parent menu is disabled while its children are enabled, only the parent menu gets hidden. As a result, the visible children seem like they are listed under the wrong parent.

The Needs Review Queue Bot → tested this issue. It fails the Drupal core commit checks. Therefore, this issue status is now "Needs work".

Apart from a re-roll or rebase, this issue may need more work to address feedback in the issue or MR comments. To progress an issue, incorporate this feedback as part of the process of updating the issue. This helps other contributors to know what is outstanding.

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Restoring status unrelated, failure.

The Needs Review Queue Bot → tested this issue. It fails the Drupal core commit checks. Therefore, this issue status is now "Needs work".

Apart from a re-roll or rebase, this issue may need more work to address feedback in the issue or MR comments. To progress an issue, incorporate this feedback as part of the process of updating the issue. This helps other contributors to know what is outstanding.

Consult the Drupal Contributor Guide → to find step-by-step guides for working with issues.

BTW, I created a module for this: admin_menu_levels →