Avoid strlen for admin submenu items

[chmst]

Pull Request for Issue #43715, #39758

Credits @Hackwar

Summary of Changes

Remove empty values from request

Testing Instructions

see #43715, #39758

Actual result BEFORE applying this Pull Request

Error message when adding or editing a menuItemType in some cases - see description in #43715, #39758

Expected result AFTER applying this Pull Request

MenuItemTypes can be selected and edited

Link to documentations

Please select:

• [ ] Documentation link for docs.joomla.org:

• [x] No documentation changes for docs.joomla.org needed

• [ ] Pull Request link for manual.joomla.org:

• [x] No documentation changes for manual.joomla.org needed

[ghost]

          The error should be triggerable with a URL like this in the manifest of a component: `index.php?option=com_foo&id[]=x`

Originally posted by @Hackwar in https://github.com/joomla/joomla-cms/issues/43715#issuecomment-2268439051

Can someone tell me where to find the "manifest"-file for "com_content" or another component (i can't trigger the bug)?

[Quy]

Please rebase for 5.2.

[Quy]

I have tested this item :white_check_mark: successfully on df46b340ef4d62be780571c15faab76db994b9af

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[viocassel]

I have tested this item :white_check_mark: successfully on df46b340ef4d62be780571c15faab76db994b9af

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[alikon]

RTC

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