Verify the access to the mdnsd socket is blocked from Android U

The untrusted apps should not directly access /dev/socket/mdnsd since
Android U(SDK 34). For untrusted apps built with target SDK 33 or less,
it should still be able to access the mdnsd socket. Fix the mts test
suits from mts-networking to mts-tethering. If the test suits is marked
as mts-networking, it would run in NetworkStack MTS, which isn't really
what is tested in the tests.

Test: atest CtsNetTestCases CtsNetTestCasesMaxTargetSdk33
Bug: 267102290
Change-Id: I851c181fa7489115fb1f335a369830078f5a5c14