Fix table column attributes for system properties

In the Web UI, when opening the spreadsheet editor on a listing of documents with columns rendering system properties (e.g. primary type, lifecycle state, ...), it does not render any columns.

How to reproduce:

• in Studio Modeler, create a page provider with the following properties:
  • Query filter: ecm:mixinType != 'HiddenInNavigation' AND ecm:isVersion = 0 AND ecm:isTrashed = 0
  • Predicates: ecm:fulltext FULLTEXT (system_fulltext)
• go to Studio Designer to configure its form and results layouts:
  • add a column with property system:primaryType in the Table of the results layout
• under Drawer > Drawer Items, add a new search item:
  • schemas: system, dublincore
  • provider: select the provider created above
  • set other mandatory properties
• deploy to a Nuxeo instance with the nuxeo-spreadsheet addon installed
• log in the Web UI
• navigate to the search created above
• switch to the table view
• open the spreadsheet editor

Expected result: the spreadsheet editor renders all the columns properly (including the primary type).
Actual result: the spreadsheet editor renders a blank page.

Notes:

• the browser's dev tool shows that the spreadsheet editor properly queries the server to retrieve the documents, but does not render anything
• this problem does not happen in the JSF UI