Add getUidRule method to BpfNetMaps

Upcoming CLs use this method to add chain status to failure log of
ConnectivityManagerTest#testFirewallBlocking which is a flaky test

Test: atest BpfNetMapsTest
Bug: 262141231
Change-Id: Ib130a28c708f675c79b889bf293dfe6b0f8d7f60
2 files changed