update magnum keystone integration to match stricter validation on api

As part of the upgrades, there was changes on the validation API that ensures that the parameters to Keystone are following the specs of the API. Now it's much more strict than before

it seems that this is passing a non valid parameter as part of the trust creation https://gitlab.cern.ch/kubernetes/magnum/-/blob/cern/train/magnum/common/keystone.py?ref_type=heads#L217

In the trust creation, delegation_depth is not even there https://docs.openstack.org/api-ref/identity/v3-ext/#os-trust-api