reverting _developer.scss partial to not clobber xblock workbench UI

apps/openassessment/xblock/static/css/openassessment.css

@@ -1525,9 +1525,6 @@ hr.divider,
   background: transparent;
   margin: 40px 40px; }
 
-.workbench .banner, .workbench .debug {
-  display: none; }
-
 .openassessment .self-assessment__display__header, .openassessment .peer-assessment__display__header, .openassessment .step__header {
   margin-bottom: 0 !important;
   border-radius: 0 !important;

apps/openassessment/xblock/static/sass/oa/utilities/_developer.scss

@@ -22,7 +22,3 @@
   background: $bg-view;
   margin: ($baseline-v*2) $baseline-h;
 }
-
-.workbench .banner, .workbench .debug {
-  display: none;
-}