Fix keyboard help dialog for RTL.

drag_and_drop_v2/public/css/drag_and_drop.css

@@ -671,10 +671,13 @@
     padding: 7px;
     background-color: #e5e5e5;
     text-align: left;
-    direction: ltr;
     z-index: 1500;
 }
 
+.rtl .xblock--drag-and-drop .modal-window {
+    transform: translate(50%, -50%);
+}
+
 .xblock--drag-and-drop .modal-dismiss-button {
     font-size: 24px;
     position: absolute;
@@ -683,6 +686,12 @@
     padding: 5px 8px;
 }
 
+
+.rtl .xblock--drag-and-drop .modal-dismiss-button {
+    right: inherit;
+    left: 3px;
+}
+
 .xblock--drag-and-drop .modal-header h2 {
     height: 30px;
     line-height: 30px;