Change snapshots format to png

Summary:
There was an issue whereas snapshots were not properly rendered on retina devices.

After running a few tests, the issue seems to be solved by changing the snapshot format from jpeg to png.

Reviewed By: antonk52

Differential Revision: D41520939

fbshipit-source-id: 1563fe89162e41f71418357a7e58caaf46581f04

desktop/plugins/public/ui-debugger/components/Visualization2D.tsx

@@ -212,7 +212,7 @@ function Visualization2DNode({
       <NodeBorder hovered={isHovered} tags={node.tags}></NodeBorder>
       {snapshot && (
         <img
-          src={'data:image/jpeg;base64,' + snapshot}
+          src={'data:image/png;base64,' + snapshot}
           style={{maxWidth: '100%'}}
         />
       )}