[neutron-lib][stable] Wallaby CI n-t-p, test "test_qos_dscp_create_and_update" failing

neutron-tempest-plugin test "test_qos_dscp_create_and_update" is failing in stable/wallaby CI. This is caused because of [1]. This patch is introducing a new DSCP mark (44). n-t-p is installing the new version and reading it but at the same time we are testing neutron-lib Wallaby, that doesn't have this patch.

In order to solve this, [2] was introduced in n-t-p. However stable/wallaby is checking out n-t-p tag 1.8.0 that doesn't have [2].

[1]https://review.opendev.org/c/openstack/neutron-lib/+/854117
[2]https://review.opendev.org/c/openstack/neutron-tempest-plugin/+/854369