Update IOpenApiResponse to derive from IOpenApiSummarizedElement

Co-authored-by: baywet <7905502+baywet@users.noreply.github.com>

Author: Copilot

src/Microsoft.OpenApi/Models/Interfaces/IOpenApiResponse.cs

@@ -6,7 +6,7 @@ namespace Microsoft.OpenApi;
 /// Defines the base properties for the response object.
 /// This interface is provided for type assertions but should not be implemented by package consumers beyond automatic mocking.
 /// </summary>
-public interface IOpenApiResponse : IOpenApiDescribedElement, IOpenApiReadOnlyExtensible, IShallowCopyable<IOpenApiResponse>, IOpenApiReferenceable
+public interface IOpenApiResponse : IOpenApiDescribedElement, IOpenApiReadOnlyExtensible, IShallowCopyable<IOpenApiResponse>, IOpenApiReferenceable, IOpenApiSummarizedElement
 {
     /// <summary>
     /// Maps a header name to its definition.

src/Microsoft.OpenApi/Models/OpenApiResponse.cs

@@ -10,7 +10,7 @@ namespace Microsoft.OpenApi
     /// <summary>
     /// Response object.
     /// </summary>
-    public class OpenApiResponse : IOpenApiExtensible, IOpenApiResponse, IOpenApiSummarizedElement
+    public class OpenApiResponse : IOpenApiExtensible, IOpenApiResponse
     {
         /// <inheritdoc/>
         public string? Summary { get; set; }
@@ -41,7 +41,7 @@ public OpenApiResponse() { }
         internal OpenApiResponse(IOpenApiResponse response)
         {
             Utils.CheckArgumentNull(response);
-            Summary = (response as IOpenApiSummarizedElement)?.Summary ?? Summary;
+            Summary = response.Summary ?? Summary;
             Description = response.Description ?? Description;
             Headers = response.Headers != null ? new Dictionary<string, IOpenApiHeader>(response.Headers) : null;
             Content = response.Content != null ? new Dictionary<string, OpenApiMediaType>(response.Content) : null;

src/Microsoft.OpenApi/Models/References/OpenApiResponseReference.cs

@@ -8,7 +8,7 @@ namespace Microsoft.OpenApi
     /// <summary>
     /// Response Object Reference.
     /// </summary>
-    public class OpenApiResponseReference : BaseOpenApiReferenceHolder<OpenApiResponse, IOpenApiResponse, OpenApiReferenceWithDescription>, IOpenApiResponse, IOpenApiSummarizedElement
+    public class OpenApiResponseReference : BaseOpenApiReferenceHolder<OpenApiResponse, IOpenApiResponse, OpenApiReferenceWithDescription>, IOpenApiResponse
     {
         /// <summary>
         /// Constructor initializing the reference object.
@@ -35,8 +35,8 @@ private OpenApiResponseReference(OpenApiResponseReference openApiResponseReferen
         /// <inheritdoc/>
         public string? Summary 
         { 
-            get => (Target as IOpenApiSummarizedElement)?.Summary; 
-            set { if (Target is IOpenApiSummarizedElement summarizedTarget) summarizedTarget.Summary = value; }
+            get => Target?.Summary; 
+            set { if (Target != null) Target.Summary = value; }
         }
 
         /// <inheritdoc/>