log errors to console instead of failing page

Previously, if there were any errors in the API docs (such as a
missing nickname) then the whole 'live' API docs page would fail
to load. This corrects the problem by making the errors into
console warnings.

Test Plan:
- load /doc/api/live
- there should be no message "SwaggerOperations must have a
  nickname" at top center
- API calls should work (with an API key set)

Fixes SIS-557

Change-Id: Iecd545564a5f7e1277b56e0a261a718c23856174
Reviewed-on: https://gerrit.instructure.com/41749
Tested-by: Jenkins <jenkins@instructure.com>
QA-Review: Jeremy Putnam <jeremyp@instructure.com>
Reviewed-by: Ken Romney <kromney@instructure.com>
Product-Review: Duane Johnson <duane@instructure.com>