Disable refund failure notification

Disable refund failure notification:

• DISABLE_REFUND_FAILURE_NOTIFICATION:

  This flag can be used to disable the edX default feature of sending refund failure notification from the edx-platform side. The default value of this is True as we are sending a refund failure emails from the ecommerce instead of edx-platform to get more error details in support email.

• Add the following changes in environment file of lms (lms.env.json) located at /edx/app/edxapp/edx-platform directory.

"FEATURES": 
{
    ...
    "DISABLE_REFUND_FAILURE_NOTIFICATION": true,
    ...
}