Fix appearance of suppress messages at Special:Undelete

This change makes 'Rev-suppressed-text-view' appear in case
suppressed page content is viewed through Special:Undelete
and 'Rev-suppressed-text-permission' in case there is a
disallowed attempt to do so.

Bug: 56380
Change-Id: I2440227b3e5a9b5baec81b57bb479ecc26052b27