Radio: get service by value.

Get strong pointer to service interface by value and not reference to
prevent race conditions where the service pointer can be cleared
by another thread while in use.

CYNGNOS-3303
Bug: 30907212
Change-Id: Iae838b3b672562c1d0cd63968399a6bfdda7f5ab
(cherry picked from commit 28a0e9ec)