Replace unsupported SOAP serialization in time zone snippet

[Copilot]

The referenced InvalidTimeZoneException snippet uses SoapFormatter, which isn't supported on modern .NET. The snippet now persists only the exception message using JSON.

• Serialization

  • Replaced SoapFormatter and IFormatter with System.Text.Json.
  • Writes the exception message to tzNotFound.json.

• Deserialization

  • Reads and deserializes the JSON message before displaying it.

string exceptionMessage = JsonSerializer.Serialize(serializedException.Message);
File.WriteAllText("tzNotFound.json", exceptionMessage);