[web/views] Fix exception in CWProperty edit form (closes #5087412)
Also add missing help message. The overall display is ugly, but at least
the message is shown.
Document: cubicweb-doc
Title: CubicWeb documentation
Author: Logilab
Abstract: Some base documentation for CubicWeb users and developpers
Section: Apps/Programming
Format: HTML
Index: /usr/share/doc/cubicweb-documentation/index.html
Files: /usr/share/doc/cubicweb-documentation/*.html