fix: v2 references for properties do not work as expected

Author: baywet

src/Microsoft.OpenApi/Models/OpenApiSchema.cs

@@ -650,7 +650,7 @@ internal void WriteAsItemsProperties(IOpenApiWriter writer)
         /// <param name="writer">The open api writer.</param>
         /// <param name="parentRequiredProperties">The list of required properties in parent schema.</param>
         /// <param name="propertyName">The property name that will be serialized.</param>
-        internal void SerializeAsV2(
+        internal virtual void SerializeAsV2(
             IOpenApiWriter writer,
             ISet<string> parentRequiredProperties,
             string propertyName)

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

@@ -227,6 +227,22 @@ public override void SerializeAsV3(IOpenApiWriter writer)
             writer.GetSettings().LoopDetector.PopLoop<OpenApiSchema>();
         }
 
+        /// <inheritdoc/>
+        internal override void SerializeAsV2(
+            IOpenApiWriter writer,
+            ISet<string> parentRequiredProperties,
+            string propertyName)
+        {
+            if (!writer.GetSettings().ShouldInlineReference(_reference))
+            {
+                _reference.SerializeAsV2(writer);
+            }
+            else
+            {
+                base.SerializeAsV2(writer, parentRequiredProperties, propertyName);
+            }
+        }
+
         /// <inheritdoc/>
         public override void SerializeAsV2(IOpenApiWriter writer)
         {