Fix formatting of mac addresses from dhcp discovery mocking in fully_kiosk (#110573)

dhcp returns addresses in lowercase without :

tests/components/fully_kiosk/test_config_flow.py

@@ -178,7 +178,7 @@ async def test_dhcp_discovery_updates_entry(
         data=DhcpServiceInfo(
             hostname="tablet",
             ip="127.0.0.2",
-            macaddress="aa:bb:cc:dd:ee:ff",
+            macaddress="aabbccddeeff",
         ),
     )
 
@@ -206,7 +206,7 @@ async def test_dhcp_unknown_device(
         data=DhcpServiceInfo(
             hostname="tablet",
             ip="127.0.0.2",
-            macaddress="aa:bb:cc:dd:ee:00",
+            macaddress="aabbccddee00",
         ),
     )