fix(openapi): hide auth header when set in securityScheme

[aheckmann]

Treat the http bearer auth security scheme the same as other security schemes by removing the authorization header.

Fixes #734

Checklist

• run npm run test and npm run benchmark <== benchmark doesn't exist so skipped that one.
• tests and/or benchmarks are included
• documentation is changed or added <== N/A
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[mcollina]

lgtm

Could the same issue show up with Swagger?

[aheckmann]

It's possible. I haven't been using it so didn't check it out.

[aheckmann]

@mcollina From what I could find, this lib already handles swagger properly b/c bearer auth does not have special handling in the spec - only OpenAPI 3 has the special bearer declaration where in is not specified.

[mcollina]

lgtm