MarkerTimeline remove hover padding

Summary: Remove the bottom padding as this was not really making it any better.

Reviewed By: antonk52

Differential Revision: D43872178

fbshipit-source-id: 8302385d190c65000afda02b5c8aa9d272ccc271

desktop/flipper-plugin/src/ui/MarkerTimeline.tsx

@@ -67,7 +67,6 @@ const Point = styled(Layout.Horizontal)<{
   lineHeight: '16px',
   ':hover': {
     background: theme.selectionBackgroundColor,
-    paddingBottom: 5,
     zIndex: 2,
     '> span': {
       whiteSpace: 'initial',