Changed Student text for unassociated Wiki
fixed issue of student getting wrong error message when wiki exists but student doesn't have permission to view (ICOMWIKI -306)
Added validation for associate screen
Merge branch 'feature/ConfluenceWiki' of github.com:Harvard-University-iCommons/icommons_lti_tools into feature/ConfluenceWiki

# By cms994
# Via cms994
* 'feature/ConfluenceWiki' of github.com:Harvard-University-iCommons/icommons_lti_tools:
  fixed issue of student getting wrong error message when wiki exists but student doesn't have permission to view (ICOMWIKI -306)
logic for case where user with instructor role does not have access to the wiki associated with the course.
Merge branch 'feature/ConfluenceWiki' into develop

# By Mysore, Sapna (2) and cms994 (2)
# Via Mysore, Sapna (1) and cms994 (1)
* feature/ConfluenceWiki:
  logic for case where user with instructor role does not have access to the wiki associated with the course.
  Added validation for associate screen
  fixed issue of student getting wrong error message when wiki exists but student doesn't have permission to view (ICOMWIKI -306)
  Changed Student text for unassociated Wiki