Add Webauthn4JRelyingPartyOperations.setObjectConverter

Simplifies testing of Webauthn4JRelyingPartyOperations

Issue gh-18158

Author: rwinch

webauthn/src/main/java/org/springframework/security/web/webauthn/management/Webauthn4JRelyingPartyOperations.java

@@ -95,7 +95,7 @@ public class Webauthn4JRelyingPartyOperations implements WebAuthnRelyingPartyOpe
 
 	private final PublicKeyCredentialRpEntity rp;
 
-	private final ObjectConverter objectConverter = new ObjectConverter();
+	private ObjectConverter objectConverter = new ObjectConverter();
 
 	private final AuthenticationTrustResolver trustResolver = new AuthenticationTrustResolverImpl();
 
@@ -137,6 +137,15 @@ public void setWebAuthnManager(WebAuthnManager webAuthnManager) {
 		this.webAuthnManager = webAuthnManager;
 	}
 
+	/**
+	 * Sets the {@link ObjectConverter} to use.
+	 * @param objectConverter the {@link ObjectConverter} to use. Cannot be null.
+	 */
+	void setObjectConverter(ObjectConverter objectConverter) {
+		Assert.notNull(objectConverter, "objectConverter cannot be null");
+		this.objectConverter = objectConverter;
+	}
+
 	/**
 	 * Sets a {@link Consumer} used to customize the
 	 * {@link PublicKeyCredentialCreationOptionsBuilder} for