Instead of calling `google::InitGoogleLogging()` directly, introduce an
indirection via a new utility library. After this change, Sandboxed API
should consistently use `sapi::InitLogging()` everywhere.
For now, `sapi::InitLogging()` simply calls its glog equivalent. However,
this enables us to migrate away from the gflags dependency and use Abseil
flags. Once a follow-up change lands, `sapi::InitLogging()` will instead
initialize the google logging library with flags defined from Aseil.
Later still, once Abseil releases logging, we can then drop the glog
dependency entirely.
PiperOrigin-RevId: 445363592
Change-Id: Ia23a7dc88b8ffe65a422ea4d5233bba7bdd1303a
