Update SurfaceModelNodesSelector.png to support its use as icon

[jcfr]

It should be a square image (at least 128x128)

Related files:

• https://github.com/saimasafdar2021/Slicer_SurfaceModelNodesSelector/blob/main/SurfaceModelNodesSelector/Resources/Icons/SurfaceModelNodesSelector.png
• https://github.com/saimasafdar2021/Slicer_SurfaceModelNodesSelector/blob/main/SurfaceModelNodesSelector.png

Related:

• Add SurfaceModelNodesSelector extension Slicer/ExtensionsIndex#2004

[saimasafdar2021]

I have successfully updated the file. its a square image 128X 128 now.