The NetworkType annotation is a hidden telephony symbol, and should be
kept hidden as annotations are disallowed by API guidelines.
Remove its usage in NetworkInfo as users of annotated constants that
build against API stubs are expected not to use the annotation.
Bug: 182451544
Test: m
Change-Id: I6658c1faa147c527c989b87d67f1af166c488dde
d4a9ed4b1a