Eliminate iOS log blacklist (#11981)

This was introduced to suppress libMobileGestalt noise originating from
libsystem_asl.dylib. Commit 39680ebfbdf787f81b5765236af0bdce9b64c9c7
suppresses all application log messages not originating from the
app/engine iteself on iOS 10 and above. Since the log message in
question is only emitted on devices running iOS >= 10.3.0, this
blacklist no longer necessary.