Flip fontawesome's icon-caret-right 180deg in rtl.

TNL-813

openassessment/xblock/static/sass/oa/elements/_navigation.scss

@@ -7,6 +7,7 @@
 // --------------------
 // collapse/expand
 // --------------------
+
 .ui-toggle-visibility {
 
   // control to toggle
@@ -23,7 +24,7 @@
 
     > .ico {
       @include transition(all $tmg-f2 ease-in-out 0s);
-      @include transform(rotate(90deg));
+      @include transform(rotate(bidi-rotate-angle(90deg)));
     }
 
     .ui-toggle-visibility__control__copy {
@@ -53,7 +54,7 @@
   &.is--collapsed {
 
     >.ui-toggle-visibility__control > .ico {
-      @include transform(rotate(0deg));
+      @include transform(rotate(bidi-rotate-angle(0deg)));
       @include transform-origin(50% 50%);
     }
 

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

@@ -641,7 +641,7 @@
         .action.expand-collapse {
           @include float(left);
           .ui-toggle-expansion {
-            @include transform(rotate(-90deg));
+            @include transform(rotate(bidi-rotate-angle(-90deg)));
             @include transform-origin(50% 50%);
             color: $edx-gray-d3;
           }
@@ -1024,7 +1024,7 @@
       .action.expand-collapse {
         @include float(left);
         .ui-toggle-expansion {
-          @include transform(rotate(-90deg));
+          @include transform(rotate(bidi-rotate-angle(-90deg)));
           @include transform-origin(50% 50%);
           .icon-caret-down:before {
             color: #009fe6;

openassessment/xblock/static/sass/oa/utilities/_mixins.scss

@@ -14,3 +14,11 @@
   }
   box-shadow: $shadow;
 }
+
+@function bidi-rotate-angle($degrees) {
+  @if $bi-app-direction == ltr {
+    @return $degrees;
+  } @else {
+    @return 180deg - $degrees;
+  }
+}