Fix highlight selection background colour

Summary: There was a regression in which the selection background color made the selection hard to read in dark mode.

Reviewed By: mweststrate

Differential Revision: D38572894

fbshipit-source-id: c46d384175132112e1223434534a379318bfa2ea

desktop/flipper-plugin/src/ui/data-inspector/DataInspectorNode.tsx

@@ -50,7 +50,7 @@ const BaseContainer = styled.div<{
   paddingLeft: 10,
   userSelect: 'text',
   width: '100%',
-  backgroundColor: props.hovered ? '#f9f9f9' : '',
+  backgroundColor: props.hovered ? theme.selectionBackgroundColor : '',
 }));
 BaseContainer.displayName = 'DataInspector:BaseContainer';