It's very easy to forget to add `require 'rails_helper'` at the top of every core/plugin spec file, and omissions can cause some very confusing/sporadic errors.
By setting this flag in `.rspec`, we can remove the need for `require 'rails_helper'` entirely.
Themes often cache `nil` values in a DistributedCache. This bug meant that we were re-calculating some values on every request, AND triggering message-bus publishing on every request.
This fix should provide a significant performance improvement for busy sites.