Use NetlinkUtils to build inet_diag_req_v2 query for TCP sockets

Construct an inet_diag_req_v2 query for TCP connections will be
used more than here later, so moving the message construction
to utils class to share between different places to reduce
duplication.

Bug: 259000745
Test: atest NetworkStackTests
Change-Id: Iaf79c594453849c6abbc57fb94957b4db3b73c8f
2 files changed