Fixed graphical issue when modifying Reflection Probe sizes

There is a graphical issue when resizing Reflection Probe box sizes on macOS. The issue comes from trying to draw in the Editor (either using `GL` commands or `DrawMeshNow`, for example) while the `Event.current.type != EventType.Repaint` causes graphical issues on Metal. This PR fixes that issue by guarding against this case when rendering the filled in box.

Jira: UUM-71467

Author: jrs-unity

Packages/com.unity.render-pipelines.core/Editor/Gizmo/HierarchicalBox.cs

@@ -190,7 +190,7 @@ public HierarchicalBox(Color baseColor, Color[] polychromeHandleColors = null, H
         public void DrawHull(bool filled)
         {
             Color previousColor = Handles.color;
-            if (filled)
+            if (filled && Event.current.type == EventType.Repaint)
             {
                 // Draw the hull
                 var xSize = new Vector3(size.z, size.y, 1f);