Initialize ProtoLog in SystemServer process

If ProtoLog is not initialized before it is used in the process we will
get RuntimeExceptions. Previously all ProtoLog calls would be processed
so the call would be re-written to use the generated ProtoLogImpl
directly. However, we now support ProtoLogging from unprocessed files
(Kotlin or Java files using new Java features) in which case the
ProtoLog static class must be initailized since in those cases we don't
go through the ProtoLogImpl generated class anymore.

Test: boot test with ag/28322001
Bug: 358044587
Flag: EXEMPT bug fix

Change-Id: Ief048131a374b51a5c535337edbe894571c2edbe