[6.3] Improved error messages when deleting a menutype

[brianteeman]

Pull Request resolves #48255 .

• 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

When deleting a menutype which contained the default menu item or had a checkout menu module the error message was the same AND it included the string "Joomla\CMS\Table\MenuType" which is not useful of user friendly

Testing Instructions

Create multiple menutype and associate a module with each
Log in as a different user and checkout one of the menu modules (not the one with the default "home" menu item)
Log back in as another user and

1. try to delete the menutype with the checkout module
2. try to delete the menutype with the default menu item

Actual result BEFORE applying this Pull Request

Both cases display the same error message

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

[richard67]

@brianteeman We had discussed the previous PR #48298 for the same issue among maintainers, and we came to the conclusion that according to the definition here https://github.com/joomla/joomla-cms#which-branch-should-my-pull-request-target it is not really bug fix and so should be handled like a feature. This means it should be rebased (or remade if that is easier due to the 6.3-dev not being up to date with 5.4-dev) for 6.3-dev. Could you do that? Thanks in advance.

[brianteeman]

will fix the conflicts later - not that happy that this minor change has to wait almost a year and other PR that are absolutely new features are still being written for 6.2

[github-actions]

This pull request has conflicts, please resolve those before we can evaluate the pull request.

[brianteeman]

conflicts resolved