Add OIDC Back-Channel Logout Support

Closes gh-12570

oauth2/oauth2-core/src/test/java/org/springframework/security/oauth2/core/oidc/TestOidcIdTokens.java

@@ -17,6 +17,7 @@
 package org.springframework.security.oauth2.core.oidc;
 
 import java.time.Instant;
+import java.util.List;
 
 /**
  * Test {@link OidcIdToken}s
@@ -32,6 +33,7 @@ public final class TestOidcIdTokens {
 		// @formatter:off
 		return OidcIdToken.withTokenValue("id-token")
 				.issuer("https://example.com")
+				.audience(List.of("client-id"))
 				.subject("subject")
 				.issuedAt(Instant.now())
 				.expiresAt(Instant.now()

oauth2/oauth2-core/src/test/java/org/springframework/security/oauth2/core/oidc/user/TestOidcUsers.java

@@ -50,7 +50,7 @@ public final class TestOidcUsers {
 				.expiresAt(expiresAt)
 				.subject("subject")
 				.issuer("http://localhost/issuer")
-				.audience(Collections.unmodifiableSet(new LinkedHashSet<>(Collections.singletonList("client"))))
+				.audience(Collections.unmodifiableSet(new LinkedHashSet<>(Collections.singletonList("client-id"))))
 				.authorizedParty("client")
 				.build();
 		// @formatter:on