Remove condition !_HttpContext.Response.HasStarted when setting session values. (#642)

It does not seem to be necessary.

Author: claudiamurialdo

dotnet/src/dotnetframework/GxClasses/Core/GXApplication.cs

@@ -1712,10 +1712,7 @@ public bool WriteSessionKey<T>(string key, T value) where T : class
 #if !NETCORE
 					HttpContext.Session[key] = value;
 #else
-					if (!_HttpContext.Response.HasStarted)
-					{
-						HttpContext.Session.SetString(key, (value != null ? JSONHelper.Serialize(value) : string.Empty));
-					}
+					HttpContext.Session.SetString(key, (value != null ? JSONHelper.Serialize(value) : string.Empty));
 #endif
 					return true;
 				}