Added the test for UID field of NetwrokDnsEventReported atom am: 21072606e4 am: 7304b76ade

Original change: https://android-review.googlesource.com/c/platform/packages/modules/DnsResolver/+/2849835

Change-Id: I48f4aa95922098ace979e49306fba935f237101c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>