netbox(role): fix oidc integration by no longer using is_staff

is_staff got removed in 4.5.0.
See: https://github.com/netbox-community/netbox/releases/tag/v4.5.0

roles/netbox/files/custom_pipeline_oidc_group_and_role_mapping.py

@@ -40,7 +40,6 @@ def remove_groups(response, user, backend, *args, **kwargs):
 def set_roles(response, user, backend, *args, **kwargs):
     # Remove Roles temporary
     user.is_superuser = False
-    user.is_staff = False
     try:
         groups = response['groups']
     except KeyError:
@@ -51,5 +50,4 @@ def set_roles(response, user, backend, *args, **kwargs):
 
     # Set roles is role (superuser or staff) is in groups
     user.is_superuser = True if 'superusers' in groups else False
-    user.is_staff = True if 'staff' in groups else False
     user.save()