INGRESS_TO_VPN_ADDRESS_FILTERING is disabled due to b/352424251 and
testDropPacketToVpnAddress fails if the feature is disabled.
So skip testDropPacketToVpnAddress if the feature is disabled.
Bug: 362434644
Test: adb shell device_config put tethering
ingress_to_vpn_address_filtering -1
Test: atest CtsHostsideNetworkTests
Change-Id: Ib16a7550dcf93dd9ecf29047b1c4f101ff6d610d