Change FrameworksVcnTests min_sdk_version to 30

FrameworksVcnTests is included in Tethering MTS. Since Tethering
is an R module, this test suite needs to be installable on R devices

Bug: 396782079
Test: presubmit
Flag: EXEMPT; test change
Change-Id: Iff6f4a5b1b949510da34ea741a55671eeff9f155