Edit breaks when the entity title is promoted to the page title

This happens since the backport of #2141055: When multiple instances of the same entity on one page, only the first can be edited, because Edit's JS tries to find the entity instance ID for the page title, but it fails to do so because the entity title is not in the expected location: it's no longer rendered inside of the entity DOM node, but outside of it. Hence we need special handling for this.