statsd: Set min_sdk_version to "30"

Just a cosmetic cleanup since "R" resolves to 30 as well.

Test: m
Bug: 171330443
Merged-In: I6c6785b93f64a89633fcc7e64116d7a2f4578d2a
Change-Id: I6c6785b93f64a89633fcc7e64116d7a2f4578d2a
(cherry picked from commit e6ea9496)