plaid
Introduce accurate error schema for object-embedded error responses
For response objects where the Error is an embedded object (e.g. Item, Wbehook responses, etc.), the schema as defined is not accurate, since it marks the field request_id as required (which will not be supplied).
This has the following side-effect: if anyone is using this open-api spec to perform response validation on the Plaid API, the validation on those objects which embed Errors will fail due to absence of the request_id field.
The the solution proposed in this PR is to introduce an ErrorBase schema which contains all the field definitions for the current Error schema EXCEPT for the request_id field. Then the Error schema is defined as the union of the ErrorBase and an object carrying only the request_id field (marked as required).
Thank you for this @ali-sharif. We will backport this change locally and create an update.
