Settings: check current ringtone for non-default sub ids

Otherwise the default phone sub's selection would always be pre-selected
regardless of the actual selection.

Ticket: CYNGNOS-2396

Change-Id: Ia33df47228eb2a49d48c80535876756b4ba1abf1
Signed-off-by: Roman Birg <roman@cyngn.com>
(cherry picked from commit 791434fd)