remove setCallIsSuppressedByDoNotDisturb in Ringer#shouldRingForContact

Dialer crashed due to a duplicate key exception. Upon inspection, the
call objects extras should not be manipulated in the Ringer class. Since
the call objects extras are already being set in
CallsManager#onCallFilteringComplete, the setter in shouldRingForContact
can be removed. This will eliminate any duplicate key bug.

Fixes: 279654232
Test:  manual tests (dnd off user alerted, dnd on call suppressed)
       testShouldRingForContact_CallShouldRing,
       testShouldRingForContact_CallSuppressed,
       testShouldRingForContact_matchesCallFilterIsAlreadyComputed
Change-Id: Ic30bbb15626bef43d0626f51d8f2b32737ca78df