Dump tcpdump on failure in testUidTagStateDetails

Add support for dumping tcpdump on test failure into the conndiag
artifact, and apply it to testUidTagStateDetails.

testUidTagStateDetails has recently been flaking due to unidentified
extra traffic, and this may help identify that traffic. Having an easy
way to collect tcpdump on test failure should help diagnose flakes going
forward as well.

Bug: 345322466
Test: atest
Change-Id: Ib2881be3df82b3b31b3a524987f775fa03279f63
2 files changed