Pull Request resolves #39967

• I read the Generative AI policy and my contribution is either not created with the help of AI or is compatible with the policy and GNU/GPL 2 or later.

Summary of Changes

In Joomla 3 we had a drop down help menu that included the possibility for a custom admin help link

Since Joomla 4 that dropdown help menu has been replaced by the complete help dashboard which is not customisable

For custom support links etc we added a specific module called login support

The admin menu module still has the field for adding the link but that link will only ever be shown if you are using the alternate preset.

This PR hides the field (to avooid confusion) using showon unless the alternate preselect is selected

Testing Instructions

In the admin menu module enter a value in the field. Observe that the link is never displayed
Change the module to use the alternate preset and observe the link is displayed in the long help menu

Apply this PR and the field is only displayed in the module form when alternate is selected

Actual result BEFORE applying this Pull Request

Expected result AFTER applying this Pull Request

Link to documentations

Please select:

• Documentation link for guide.joomla.org:

• No documentation changes for guide.joomla.org needed

• Pull Request link for manual.joomla.org:

• No documentation changes for manual.joomla.org needed