Add Ping4 offload for APFv6 multi-devices tests

Introduce Ping4 offload support for improved APFv6 multi-device testing.
Adds a decorator to restrict tests to Android B+ capable client device.

Test: m connectivity_multi_devices_snippet && atest CtsConnectivityMultiDevicesTestCases
Change-Id: I01909c1725ba471726223deef325c3f0a80b5c14
diff --git a/tests/cts/multidevices/Android.bp b/tests/cts/multidevices/Android.bp
index a082a95..39cb0ad 100644
--- a/tests/cts/multidevices/Android.bp
+++ b/tests/cts/multidevices/Android.bp
@@ -29,6 +29,7 @@
     libs: [
         "absl-py",
         "mobly",
+        "scapy",
         "net-tests-utils-host-python-common",
     ],
     test_suites: [