This test failure was caused by rails calling `.debug` on our FakeLogger which was not supporting it, resulting in more errors than what the test was expecting.
This change both speeds up specs (less strings to allocate) and helps catch
cases where methods in Discourse are mutating inputs.
Overall we will be migrating everything to use #frozen_string_literal: true
it will take a while, but this is the first and safest move in this direction
We had a missing formats: string on our render partial that caused logs to
spam when CSS files got 404s.
Due to magic discourse_public_exceptions.rb was actually returning the
correct 404 cause it switched format when rendering the error.
