This commit enhances the stability of the APFv{4,6} multi-device tests by addressing several sources of flakiness and improving the test setup and validation.
Specifically, this commit:
* Increased sleep time in the test setup. This ensures APF is activated before each test, preventing unexpected behavior.
* Added sleep time in `ApfV4Test` to ensure APF remains enabled and is not disabled due to high throughput scenarios.
* Changed the validation order to first check received packets and then APF counters. This helps to more easily identify the root cause of test failures.
* Changed the Ethernet destination address from multicast to unicast in `ApfV6Test` to prevent packets from being filtered due to DTIM skip.
* Removed the `test_broadcast_arp_request_offload()` test, which was flaky due to DTIM skip and is adequately covered by the `test_unicast_arp_request_offload()` test.
Bug: 406570694
Flag: TEST_ONLY
Test: atest CtsConnectivityMultiDevicesTestCases:ApfV4Test
Test: atest CtsConnectivityMultiDevicesTestCases:ApfV6Test
Test: run cts -m CtsConnectivityMultiDevicesTestCases --skip-preconditions -t ApfV4Test --shard-count 2
Test: run cts -m CtsConnectivityMultiDevicesTestCases --skip-preconditions -t ApfV6Test --shard-count 2
Change-Id: I053509459078d0bd94e16a6bf7349b948f930e6c
744a17443a