Ability to pass setFieldOptions() parameter to define the date_format

[hazemhamedhs]

This is a parameter that allows requester to specify field options for a signature request. This include the
date_format: [string] to allow the requester to specify the date format (see list of allowed formats)

https://app.hellosign.com/api/reference#send_embedded_signature_request
Internal ask [AS-245]