Improve support for right to left languages

lms/static/sass/discussion/elements/_actions.scss

@@ -295,6 +295,7 @@
 
   .action-button, .action-list-item {
     .action-label {
+      @include float(left);
       .label-checked {
         display: none;
       }

lms/static/sass/discussion/views/_thread.scss

@@ -44,7 +44,7 @@ body.discussion, .discussion-module {
 
     .response-header-actions {
       position: absolute;
-      right: ($baseline);
+      @include right($baseline);
       top: ($baseline);
       @include float(right);
     }