Add androidx.annotation_annotation dependency.

stats-log-api-gen adds missing @RequiresApi annotations to the generated
StatsLog.write() calls. The library pulling in the changes needs to
depend on androidx.annotation_annotation which provides @RequiresApi
annotation.

Bug: 319044160
Test: m
Change-Id: Icf66ea609b4ef709f8d86f99e016a206dd437cab