Cleanup raw OpenApiJson schema reading. Remove special attribute RefDescription as it's in a transformer

Author: desjoerd

src/OpenApi/src/Schemas/OpenApiJsonSchema.Helpers.cs

@@ -350,11 +350,6 @@ public static void ReadProperty(ref Utf8JsonReader reader, string propertyName,
                 schema.Metadata ??= new Dictionary<string, object>();
                 schema.Metadata[OpenApiConstants.RefId] = reader.GetString() ?? string.Empty;
                 break;
-            case OpenApiConstants.RefDescriptionAnnotation:
-                reader.Read();
-                schema.Metadata ??= new Dictionary<string, object>();
-                schema.Metadata[OpenApiConstants.RefDescriptionAnnotation] = reader.GetString() ?? string.Empty;
-                break;
 
             default:
                 reader.Skip();