static OidcIdTokenClaimCollector listableCollector() {
        return JwtClaims::setClaim;
    }
Listable collector forces all claims to be collected
as list regardless of the number of values found for the claim.

@return the oidc ID token claim collector
support/cas-server-support-oidc-core-api/src/main/java/org/apereo/cas/oidc/claims/OidcIdTokenClaimCollector.java