Could you please add a 'Sandbox' option in the Square non-merchant gateway within Blesta ?

Square developer docs link here:
https://developer.squareup.com/docs/devtools/sandbox/overview

In short, if option is unchecked (default), the base URL for all API requests made by the module is:

https://connect.squareup.com/v2/

.... and if the option is checked, the base URL for all API requests made by the module should be:

https://connect.squareupsandbox.com/v2/