Keyboard shortcuts: UI polish 2

1. Changed list title from body1 (14sp, regular) to
body2 (14sp, bold).

2. Reduced spacing between list title and first list item
by 3dp

3. Reduced height from divider line to list by 20dp (I had
this in redlines as 20dp, but I think that added an
additional 20dp to the component so it ended up being
40dp in implementation)

4. Reduced padding between app icon and app name from 32dp
to 24dp (this is a change from original redlines so that
the text aligns 72dp from the edge of the dialog which is
a standard Material keyline)

Bug: 28169928
Change-Id: I01b92486353fa990158819a2d18b16cd910d7ded