Merge "StatsMapKey.java - uid U32 -> S32" am: f4913b1323

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2218549

Change-Id: Iebae79ff66ac5cee0a8d5171767ede9cc39332de
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>