Create a new Exception type for a dynamic prop missing a host entity

Overview

Follow-up to 📌 Lift most logic out of ComponentTreeItem::preSave() and into a new validation constraint Needs work . see https://git.drupalcode.org/project/experience_builder/-/merge_requests/6...

in that issue we ignored and OutOfRangeException if the component tree was config because at that point we don't have a host entity.

Proposed resolution

Make new exception type for when the host entity is missing.