Embedding a display in an other with a formatter

Problem/Motivation

Embedding a display in an other with the ui_patterns_field's Source field, it was supposed to work with what we already have, but it doesn't.

Proposed resolution

We have 4 situation to checks when I embed a display (teaser) in the other (full/default) with the ui_patterns_field's: Render Source formatter:

• None of them are overridden: ❌ The teaser is not visible, which may be normal because nothing is stored in the field
• Only Teaser is overridden: ❌ The teaser is not visible, and that's worrying
• Only Default is overridden: PENDING
• Both are overridden: PENDING

Once it works, check also:

• What is happening when we put the formatter of a display in the same display ? Infinite recursion?
• Is it a way of implementing lock mechanism like layout_builder_lock → is providing? If it is enough, let's check this and document this. It not, we may need to create a dedicated issue (see description of 📌 [1.0.0-alpha2] Add content display overrides Active ) but we need to be sure we are not blocking anything