[Generic] Signature

[Generic] Signature is a small subflow that takes the language code as an input and returns the appropriate response signature based on the language. For example, if the language code is "en", the subflow will return "Sincerely, ... ". If the language code is "fr", the subflow will return "Cordialement, ...".
The subflow uses a switch node to handle different language codes and a default case for unsupported languages.