SAML2 Scoping still uncovered by unit tests

[peppelinux]

Recently we added support for SAML2 Scoping but this is still uncovered by tests. see:

https://github.com/IdentityPython/djangosaml2/blob/86a5dc792e29e873714b18600f17e0d7b7e8d657/djangosaml2/views.py#L195

@pauldekkers ^