fix hashcode

Src/Dlhis.ScheduledTask/Common/GetHashCodeExtensions.cs

@@ -5,6 +5,7 @@ internal static class GetHashCodeExtensions
     public static int SafeGetHashCode(this object o)
     {
         if (o == null) return 0;
+        if(string.IsNullOrEmpty(o.ToString())) return 0;
         return o.GetHashCode();
     }