Lists the tags assigned to a workflow. Tags are multi-select, so the
result is a list. A well-formed workflow id with no tag rows returns an
empty list. A malformed id is rejected with 400 before the lookup.

Tags are returned in the same shape as getTag / listTags, so a tag
id from this response can be looked up directly via GET /v1/tags/:id
or filtered via GET /v1/tags?type=workflow.

OAuth callers require the workflows:read scope.