Add resize icon to inspector preview and replace preview node resize handle with temporary icon

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Resources/Styles/MaterialGraph.uss

 }
 
 MaterialNodeView > #resize {
-    background-color: rgb(0, 0, 255);
+    background-image : resource("GraphView/Nodes/NodeChevronLeft.png");
-}
-
-MaterialNodeView > #resize:hover {
-    background-color: rgb(0, 127, 127);
-}
-
-MaterialNodeView > #resize:active {
-    background-color: rgb(0, 225, 25);
+    cursor: resize-up-left;
 }
 
 PortInputView {
     padding-bottom: 10;
 }
 
+GraphInspectorView > #bottom {
+    margin-bottom: 20;
+}
+
-    height: 400;
+    max-height: 400;
     background-color: rgb(79, 79, 79);
 }
 
 
 GraphInspectorView > #resize {
     cursor: resize-up-left;
-    align-self: flex-end;
-    background-color: rgb(0, 0, 127);
+    background-image : resource("GraphView/Nodes/NodeChevronLeft.png");
     position-type: absolute;
     width: 16;
     height: 16;