MarkerTimeline remove top margin of Time

Summary: The margin was miss-aligning with the label.

Reviewed By: antonk52

Differential Revision: D43872373

fbshipit-source-id: 8a6ff8104c6e532d8139053aad221244c2cd5feb

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

@@ -112,7 +112,6 @@ const Time = styled.span({
   color: theme.textColorSecondary,
   fontWeight: 300,
   marginRight: 4,
-  marginTop: -2,
 });
 Time.displayName = 'MakerTimeline:Time';