Follow-up to #784 and #788

Description

When generating a new EA with yarn new, it includes an integration test but only unit tests for http and ws transports.
This PR adds a unit test for customBg transports.

Changes

1. In the generated CustomBg transport file:
   1. Use the name of the endpoint in the transport name, is we usually do manually.
   2. Initialize config and endpointName.
   3. Add logic to use the requester.
2. Add a customBg unit test template.
3. Use the template to generate the unit test.
4. Update the integration test to match the new logic in the generated transport.

Testing

1. We have a workflow that generates an adapter that still passes.
2. I manually tested it in external-adapters-js to create an adapter with a single endpoint called abc-def with a single customBg transport. The generated tests passed.