[DOC] - Audit and update TCR endpoints

[hey-august]

Describe the requested update
Customer reports issues with TCR endpoints in the REST API docs. (Via Peter in Slack). Endpoint behavior should be compared to docs and the spec should be updated.

Reason for the request
The TCR endpoints appear to behave differently than documented. Particularly, it appears that responses to brand creation and retrieval don't include some items described in the Response section of the docs for those endpoints.

Sections to be updated
SignalWire REST API spec and generated docs