How can I disable the FYI notification when a Supplier becomes Spend Authorized?

When our client registers a new supplier - they get an FYI notification that their supplier registration request was approved. However, when the supplier is approved for spend authorized, they also get an FYI notification.

Our client would like to turn off the Spend authorized FYI notification only (as suppliers will be auto-approved for spend authorized anyway). Does anyone know if this is possible?