REFACTOR: Remove Discourse.HighlightJSPath from globals

Instead we use the session, and pass that along where necessary.

app/assets/javascripts/admin/components/highlighted-code.js

@@ -5,7 +5,7 @@ import highlightSyntax from "discourse/lib/highlight-syntax";
 export default Component.extend({
   @on("didInsertElement")
   @observes("code")
-  _refresh: function() {
-    highlightSyntax($(this.element), this.siteSettings);
+  _refresh() {
+    highlightSyntax($(this.element), this.siteSettings, this.session);
   }
 });

app/assets/javascripts/admin/models/theme.js

@@ -313,7 +313,7 @@ const Theme = RestModel.extend({
           }
         );
         // TODO: Models shouldn't be updating the DOM
-        highlightSyntax(undefined, this.siteSettings);
+        highlightSyntax(undefined, this.siteSettings, this.session);
       } else {
         return this.save({ remote_update: true }).then(() =>
           this.set("changed", false)