catch fatal exception when fetching rintone that doesnt exist

A user proved it was possible to cause the device to reboot when
the current ringtone file no longer exists but is still the default.
Ideally, if there is an issue fetching the ringtone, this shouldnt
cause the device to reboot and catch any exception that may occur.

bug: 264344702
Test: manual
Change-Id: I0def15a905c4cfd31b51cad910852fac414b6a36