SpringBoot Provide a configuration property for configuring a relying party registration's name ID format

Support for NameIdFormat was introduced in https://github.com/spring-projects/spring-security/issues/9115, but there is not a corresponding property in Saml2RelyingPartyProperties, and Saml2RelyingPartyRegistrationConfiguration does not set any value on the RelyingPartyRegistration.

Comment From: BenchmarkingBuffalo

Hi @wilkinsona I would like to work on this issue. If you want, you can assign it to me.

Comment From: scottfrederick

Closing in favor of #39395