lineage: enable roundIcons by default

We're using circular shape for adaptive icons,
by turning roundIcons on we either get
better circular icons (for apps such as Chrome) or
the same icons as before.

Trebuchet will still allow to swap icons shape

Change-Id: If64ecb427b98e099c55fd3eebdb49dad9cb3dbf2
Signed-off-by: Joey <joey@lineageos.org>