!466 update Admin.NET/Admin.NET.Core/Util/LongJsonConverter.cs.

Merge pull request !466 from MICZ/N/A

Admin.NET/Admin.NET.Core/Util/LongJsonConverter.cs

@@ -1,4 +1,4 @@
-using Newtonsoft.Json.Linq;
+using Newtonsoft.Json.Linq;
 
 namespace Admin.NET.Core;
 
@@ -15,6 +15,6 @@ public class LongJsonConverter : JsonConverter<long>
     public override long ReadJson(JsonReader reader, Type objectType, long existingValue, bool hasExistingValue, JsonSerializer serializer)
     {
         JToken jt = JValue.ReadFrom(reader);
-        return jt.Value<long>();
+        return string.IsNullOrWhiteSpace(jt.Value<string>())?0: jt.Value<long>();
     }
 }