[Thread] remove CtsThreadNetworkTestCases from CTS test suite

Ideally b/308147861 should be resolved by ag/25218374, but
unfortunately, the flagging infra structure doesn't support it well (see
b/308534973).

This commit removes CtsThreadNetworkTestCases from the cts suite temporarily
to unblock b/308147861. It's okay given our API and CTS tests is
targeting Android V.

Ignore-AOSP-First: fix test issues on internal "next" builds
Bug: 308147861
Test: verified that CtsThreadNetworkTestCases doesn't fail for
v2/android-xts/cts/framework/device-release

Change-Id: I43ac18f1289d6c1cdc8144c9dcf21b4d630c609c
1 file changed