Add missing @OrasModel annotation on CredentialHelperResponse (#685)

Signed-off-by: Thomas Vitale <ThomasVitale@users.noreply.github.com>

Author: ThomasVitale

src/main/java/land/oras/auth/AuthStore.java

@@ -341,6 +341,7 @@ public Credential(String username, String password) {
      * @param username The username
      * @param secret The secret (password or token)
      */
+    @OrasModel
     public record CredentialHelperResponse(
             @JsonProperty("ServerURL") String serverUrl,
             @JsonProperty("Username") String username,

src/test/java/land/oras/ClassAnnotationsTest.java

@@ -49,7 +49,7 @@ void shouldHaveAnnotationOnModel() {
                     .loadClasses());
 
             // Check number of classes
-            assertEquals(25, modelClasses.size());
+            assertEquals(26, modelClasses.size());
 
             // Check classes
             assertTrue(modelClasses.contains(Annotations.class));
@@ -83,7 +83,7 @@ void shouldHaveAnnotationOnAuthPackage() {
                     .loadClasses());
 
             // Check number of classes
-            assertEquals(7, modelClasses.size());
+            assertEquals(8, modelClasses.size());
         }
     }
 }