Remove yaml stdout_callback plugin from network-integration tests (#67203)

With the move to collections, yaml is no longer in ansible base. Switch
back to default stdout.

Signed-off-by: Paul Belanger <pabelanger@redhat.com>

test/integration/network-integration.cfg

@@ -4,7 +4,6 @@
 [defaults]
 host_key_checking = False
 log_path = /tmp/ansible-test.out
-stdout_callback = yaml
 
 [ssh_connection]
 ssh_args = '-o UserKnownHostsFile=/dev/null'