WebUI interface should not allow DirectEdit button on proxies

For a proxy, for which the associated binary cannot be modified whatever the permissions set on the proxy, the WebUI interface should act the same as the JSF interface; do not propose the DirectEdit button.

To reproduce;

• create a group ReadWriteOnSection with a user test in this group
• create a Section s with ReadWrite permission for ReadWriteOnSection
• publish a document Doc in the section s
• login as user test and for the document Doc in section s, observe the DirectEdit possibility is proposed in WebUI
• now, in JSF, for the same document, observe that Doc in section s proposes no DirectEdit action

Expected; no DirectEdit button for proxies in WebuI