Merge pull request #1467 from Unity-Technologies/sg/fix-for-preview-being-infront-of-outliner

Outliner and preview fix

com.unity.shadergraph/CHANGELOG.md

 - Your system locale can no longer cause incorrect commands due to full stops being converted to commas.
 - Deserialization of subgraphs now works correctly.
 - Sub graphs are now suffixed with (sub), so you can tell them apart from other nodes.
+- The preview of a node does not obstruct the selection outliner anymore.

com.unity.shadergraph/Editor/Drawing/Views/MaterialNodeView.cs

                 if (m_PreviewContainer.parent != this)
                 {
                     Add(m_PreviewContainer);
+                    m_PreviewContainer.PlaceBehind(this.Q("selection-border"));
                 }
                 m_PreviewFiller.AddToClassList("expanded");
                 m_PreviewFiller.RemoveFromClassList("collapsed");