Render the "basic" metatag group on initial load instead of a button-only widget

Problem/Motivation

The async widget currently renders a button-only widget on the content edit form ("Customize meta tags"). Editors must click the button and wait for an AJAX round-trip before they can see or edit any meta tags — including the most common ones (page title, description) that live in the basic group. For a site where editors routinely set the basic tags, that extra click + AJAX rebuild is friction on every node edit.

Proposed resolution

Render only the basic group on initial page load, and keep an AJAX button to lazy-load the remaining groups on demand. This gives editors immediate access to the common tags while still deferring the expensive full build.

Remaining tasks

Add/adjust tests.

User interface changes

Basic Metatags will render on initial page load, remaining all metatags will be hidden by default and will only load on click of button.