Design: Update color/emoji picker drop shadow

[paninaro]

Current style:

  const pickerStyle: any = {
    backgroundColor: isDark ? Color.Neutral[800] : Color.Neutral[50],
    border: `1px solid ${isDark ? theme.palette.border.dark : theme.palette.border.main}`,
    boxShadow: `0px 6px 19px ${alpha(Color.Neutral[800], 0.28)}, 0px 27px 65px ${alpha(Color.Neutral[500], 0.39)}`,
    borderRadius: '8px',
    padding: '0px',
    position: 'absolute',
    top: '30px',
    left: '25px',
  };

[paninaro]

Updated. In dark mode, the drop shadow is gone per a discussion with design.