only show copy all action menu item if the field is part of an element

[i-just]

Description

Prevents the “Copy all {type}” action menu item from showing for the Matrix field outside an element context.

I also opened a second PR for this issue, which prevents the item from being added altogether, instead of only hiding it when the disclosure menu is opened; however, it contains a potentially breaking change, so it’s targeting 5.8 for now.

Note: In 5.8, there are additional Expand and Collapse action menu items, which are already hidden when the disclosure menu is opened.

Related issues

#17404