[4.2] tag selection in article category menus

[brianteeman]

Related Pull Request for Issue #38087 .

Summary of Changes

When creating a menu item of type article-category or article-list you can filter by tags.
This PR Prevents the ability to create new tags when selecting tags. They're not actually created anyway and it doesnt make sense that you would be able to create a new tag here anyway.

This PR uses a field attribute custom="deny" to prevent the fake ability to create a new tag.

Testing Instructions

Create a few articles with tags
Create an arrticle categoru blog and categpory list menu and select existing tags AND try to type in a non-existing tag and hit enter

Before

After

[ghost]

I have tested this item ✅ successfully on 72b8d08

Test on menu item type Category Blog and Category List.

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[ChristineWk]

I have tested this item ✅ successfully on 72b8d08

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[alikon]

RTC

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[roland-d]

Thanks everybody