Use e2e firewall in all linode interface tests (#685)

Author: zliang-akamai

test/integration/conftest.py

@@ -16,7 +16,6 @@
 from requests.exceptions import ConnectionError, RequestException
 
 from linode_api4 import (
-    ExplicitNullValue,
     InterfaceGeneration,
     LinodeInterfaceDefaultRouteOptions,
     LinodeInterfaceOptions,
@@ -645,7 +644,7 @@ def linode_with_linode_interfaces(
                 public=LinodeInterfacePublicOptions(),
             ),
             LinodeInterfaceOptions(
-                firewall_id=ExplicitNullValue,
+                firewall_id=e2e_test_firewall.id,
                 vpc=LinodeInterfaceVPCOptions(
                     subnet_id=subnet.id,
                 ),