Temporary fix: Don't use ember imports in pretty text

app/assets/javascripts/discourse-loader.js

@@ -31,6 +31,12 @@ var define, requirejs;
         inject: Ember.inject.service
       }
     };
+  } else if (typeof __PRETTY_TEXT !== "undefined") {
+    // This is a hack because our server side code includes the pretty_text bundle
+    // which relies on ember now that we're using modules properly.
+    // The proper fix would be to move the upload urls code out of the pretty text
+    // bundle and remove this code. It should never be called;
+    EMBER_MODULES["@ember/runloop"] = {};
   }
 
   var _isArray;