Add 'View Consent' button to dashboard when required

Enterprise customers can require user to agree to Data Sharing Consent
form before they can access a course. We now add it conditionally to
Course Dashboard when it's required so it's apparent to user and they
have a way to revist the consent form if they've previously declined or
the course has not yet started.

WL-1281

lms/static/sass/multicourse/_dashboard.scss

@@ -721,7 +721,7 @@
 
         @include clearfix();
 
-        position: relative;
+        position: inherit;
 
         @include left($baseline/2);
         @include padding(($baseline * 0.4), 0, ($baseline * 0.4), ($baseline * 0.75));
@@ -772,6 +772,15 @@
           opacity: 0.875;
         }
       }
+
+      .action-view-consent {
+        @extend %btn-pl-white-base;
+        @include float(right);
+              
+        &.archived {
+          @extend %btn-pl-default-base;
+        }
+      }
     }
 
     // TYPE: status