Rebuild the dynamic path before validating it
What does this MR do?
Instead of validating the old Routable#full_path when updating the path attribute, the DynamicPathValidator will now rebuild the full path to be validated. That way the path has the updated attribute before checking.
Why was this MR needed?
Without this, it would be possible to update a path to something reserved. Since the validation would happen on the old full path that was loaded & cached.
Closes #33746 (closed)