[BUG]Remove braintree rest api transformers

[srujanchikke]

I've found this bug while creating payment connector account for braintree. Validation for metadata is added for braintree graphql metadata but not for braintree REST api. Anyway's as braintree REST api is getting deprecated so need to remove code from codebase .

[AkshayaFoiger]

Yes as stated, the metadata validation is not implemented for Braintree Rest API.

We depreciate Braintree Rest API.
Therefore we are not expecting to add the required validation. However in the current system, as metadata needed for both braintree transformers are same, Braintree REST API requests are validated by a common validation check present in Braintree graphql transformer.

Hence, closing the issue