correctly serialize decimal total seconds of TimeSpan into a json number

Author: zrckr

Core/Helpers/Json/CustomConverters/TimeSpanJsonConverter.cs

@@ -18,7 +18,7 @@ public override void Write(
             TimeSpan timespan,
             JsonSerializerOptions options)
         {
-            writer.WriteRawValue($"{timespan.TotalSeconds}");
+            writer.WriteNumberValue((decimal)timespan.TotalSeconds);
         }
     }
 }