Follow up to:

• Pattern: patterns in content only mode need a way to be "unlocked" or "detached" #71558

The objective is to allow users to edit the contents of a content only pattern without permanently detaching the pattern from its "content only" status.

Behind this is the concept that clicking on "Edit contents/blocks/whatever" shouldn’t be a persistent change. For example, when you reload the browser the pattern should revert to being a pattern block again.

Some ideas:

• Edit a content only pattern in "focussed" or spotlight view, similar to the way the navigation and template parts are edited
• Change the behaviour of the “Edit contents” button, e.g., when it's activated the inner blocks are editable, either clicking it again revert back to content only editing