Plaid Get RTP eligibility information of a transfer

Use the `/transfer/capabilities/get` endpoint to determine the RTP eligibility information of a transfer. To simulate RTP eligibility in Sandbox, log in using the username `user_good` and password `pass_good` and use the first two checking and savings accounts in the "First Platypus Bank" institution (ending in 0000 or 1111), which will return `true`. Any other account will return `false`.