Clear calling identity when notifying alert/limit reached

When the NetworkStatsProvider reports alert/limit reached,
NetworkStatsService will relay the event to other services
such as NPMS or NMS. The identity should be cleared before
calling into other services.

Test: TH
Bug: 181106917
Change-Id: I2a7b273dc30156a84b30566319894ec3a42d4429
1 file changed