[saml2] in idp_slo, send all known session indexes for the current session and the given provider
[saml2] in idp_slo, send all known session indexes for the current session and the given provider

That's needed for SLO to work in most cases.

incuna/authentic,incuna/authentic,incuna/authentic,pu239ppy/authentic2,adieu/authentic2,incuna/authentic,adieu/authentic2,pu239ppy/authentic2,BryceLohr/authentic,incuna/authentic,adieu/authentic2,pu239ppy/authentic2,BryceLohr/authentic,BryceLohr/authentic,adieu/authentic2,pu239ppy/authentic2,BryceLohr/authentic