UI Scaling Fixes for do_after and PopupMessage (#2737)

* Fixes do_after bar placement when using UI scaling

* Add Scaled Screen Position debug overlay to DebugCoordsPanel
Fix PopupMessage being in the wrong location when using UI scaling

* Fix warning

Content.Client/GameObjects/EntitySystems/DoAfter/DoAfterBar.cs

@@ -117,7 +117,7 @@ namespace Content.Client.GameObjects.EntitySystems.DoAfter
             var box = new UIBox2i(
                 leftOffset,
                 -2 + 2 * DoAfterBarScale,
-            leftOffset + (int) (XPixelDiff * Ratio),
+            leftOffset + (int) (XPixelDiff * Ratio * UIScale),
             -2);
             handle.DrawRect(box, color);
         }