Added the SamplerState presenter

MaterialGraphProject/Assets/UnityShaderEditor/Editor/Drawing/Presenters/MaterialGraphPresenter.cs

             typeMapper[typeof(TextureSamplerNode)] = typeof(TextureSamplerNodePresenter);
             typeMapper[typeof(TextureAssetNode)] = typeof(TextureAssetNodePresenter);
             typeMapper[typeof(TextureLODNode)] = typeof(TextureLODNodePresenter);
+            typeMapper[typeof(SamplerStateNode)] = typeof(SamplerStateNodePresenter);
             typeMapper[typeof(CubemapNode)] = typeof(CubeNodePresenter);
 			typeMapper[typeof(ToggleNode)] = typeof(ToggleNodePresenter);
             typeMapper[typeof(UVNode)] = typeof(UVNodePresenter);