SAML 2.0 Asserting Party Metadata resolution should read SigningMethod elements #9177
Description
Asserting party metadata should indicate what signing methods it supports (section 2.4). This is valuable when the relying party signs its AuthnRequests or LogoutRequests and needs to use an algorithm supported by the asserting party.
When an asserting party uses <SigningMethod>, the OpenSamlAssertingPartyMetadataConverter should add it into the RelyingPartyRegistration it is building.
Related to #8952.