add a [JsonProperty("name")] attribute here for consistency with the JSON contract

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: KoditkarVedant

Src/Notion.Client/Models/File/FIleInput/ExternalFileInput.cs

@@ -8,6 +8,7 @@ public class ExternalFileInput : IFileObjectInput
         [JsonProperty("external")]
         public Data External { get; set; }
 
+        [JsonProperty("name")]
         public string Name { get; set; }
 
         public IEnumerable<RichTextBaseInput> Caption { get; set; }