Always remove message string argument from processed calls

There is no longer a valid log call were both the log message hash and the message are passed.

Flag: android.tracing.perfetto_protolog_tracing
Test: atest com.android.protolog.tool.ProtoLogCallProcessorImplTest
Change-Id: Ifd77205405d2ba1cefafb03e89b484dbda1b20c8