fixes #7314 - Set settings explicitly instead of stubbing Settings

`test_successful_smart_proxy_authentication_in_api_controller` in `test/functional/smart_proxy_auth_test.rb` is failing in my plug-in, although it's not a valid failure.

The Foreman test just outright stubs auth_smart_proxy to be true, however, this doesn't seem to stub out the plug-in's chain method.  My chained method called a Setting that's not stubbed, which results in this failure:

    unexpected invocation: Setting(id: integer, name: string, value: text, description:
    text, category: string, settings_type: string, default: text, created_at: datetime,
    updated_at: datetime).[](:require_ssl_puppetmasters)...

It seems the easiest solution here is to not be stubbing settings, as just setting them outright works in most cases. The only exception I see is the seeds_test, which is fine as is.

I can also just wait until plug-ins can disable Foreman tests, but I'd rather not disable any unless I have to.  This fixes the last failing test for foreman_salt (hopefully).