Use unicast instead of broadcast as ethernet destination in `test_apf_drop_ethercat`

To prevent packet dropped earlier by multicast filtering,
use unicast ethernet destination instead

Bug: 360730207
Test: m connectivity_multi_devices_snippet && atest CtsConnectivityMultiDevicesTestCases:ApfV4Test
Change-Id: I4816b71f68f349abf1423c7013bb058ccc233d61
diff --git a/staticlibs/testutils/host/python/apf_test_base.py b/staticlibs/testutils/host/python/apf_test_base.py
index 9a30978..891876b 100644
--- a/staticlibs/testutils/host/python/apf_test_base.py
+++ b/staticlibs/testutils/host/python/apf_test_base.py
@@ -50,6 +50,9 @@
     self.server_mac_address = apf_utils.get_hardware_address(
         self.serverDevice, self.server_iface_name
     )
+    self.client_mac_address = apf_utils.get_hardware_address(
+        self.clientDevice, self.client_iface_name
+    )
 
     # Enable doze mode to activate APF.
     adb_utils.set_doze_mode(self.clientDevice, True)
diff --git a/tests/cts/multidevices/apfv4_test.py b/tests/cts/multidevices/apfv4_test.py
index 7795be5..aa535fd 100644
--- a/tests/cts/multidevices/apfv4_test.py
+++ b/tests/cts/multidevices/apfv4_test.py
@@ -53,7 +53,7 @@
   )  # Declare inputs for state_str and expected_result.
   def test_apf_drop_ethertype_not_allowed(self, blocked_ether_type):
     # Ethernet header (14 bytes).
-    packet = ETHER_BROADCAST_ADDR  # Destination MAC (broadcast)
+    packet = self.client_mac_address.replace(":", "")  # Destination MAC
     packet += self.server_mac_address.replace(":", "")  # Source MAC
     packet += blocked_ether_type