Improve message in PathWidget

Problem/Motivation

Follow up from #3342398: Path module calls getInternalPath without checking if the url is routed #35

Since this will show in the UI I think it should be easier for an admin to understand and to fix. And it should not continue to use 'unrouted' which is a misspelled word in the dictionary. From the IS I gather that this is an uncommon case. Therefore, how about we at least avoid the spelling error and make a followup, tagged usability, to improve the message. Unless someone has a better idea how about, "An entity without a route cannot have a path."?

Steps to reproduce

NA

Proposed resolution

TBD

Remaining tasks

Come up with new message

User interface changes

TBD

API changes

TBD

Data model changes

TBD

Release notes snippet

TBD