Listen for ‘blur’ on mini editor of select list rather than ‘focusout’

The focusout handler on the mini editor’s hidden input wasn’t being
triggered, but we can listen for blur directly on the editor now that
the shadow DOM abstracts the focus.
Define enter as ‘core:confirm’ in select-list mini editors

We were leaving this to packages to define, and they were getting it
wrong by selecting into the ‘input’ which is now in shadow.