Fix element 'nuxeo-clipboard' when it copies/moves a proxy in a section

When the clipboard contains a proxy and the user navigates to a section, the COPY and MOVE buttons stay disabled. This behavior was introduced by NXP-27451, which checks the allowed sub-types of the target folderish document. In the case of a section, the allowed sub-types should not be checked, the publishing service does not check the allowed sub-types when it creates the proxy (in the section when a document is published, the clipboard does not need to make this check neither.

How to reproduce:

• log in the Web UI
• create a File document in a workspace and publish it in a section
• navigate to the section and add the published document/proxy to the clipboard
• navigate back to the workspace
• open the clipboard sidebar and click on the MOVE button to move the proxy to the workspace
• add the same proxy (you just moved) to the clipboard again
• navigate back to the section
• open the clipboard sidebar to move the proxy back to the section

Expected result: the clipboard sidebar has buttons MOVE and COPY enabled
Actual result: the buttons MOVE and COPY in the clipboard sidebar are disabled