Supporting ForceAuthn SAML request attribute

[MohammedAlmeshal]

Hello @mostafa,

This PR adds support for optionally configuring the ForceAuthn attribute in SAML requests. The attribute is defaulted to False and can be configured through the setting field FORCE_AUTHN, which will be mapped to pysaml2's force_authn configuration directive.

I haven't found an appropriate way to test it; would appreciate your guidance if needed.

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[mostafa]

LGTM! Thanks for your contribution! 🙏

I'm not sure about testing either. 🤷‍♂️ Have you tested this with your IdP for acceptance?

[MohammedAlmeshal]

Yes, I tested it against my IdP with all the values, and it is working as expected.
My pleasure, thank you for making my first OS contribution so enjoyable ❤️