If a plugin's JS fails to load for some reason, most commonly
ad blockers, the entire admin interface would break. This is because
we are adding links to the admin routes for plugins that define
them in the sidebar.
We have a fix for this already in the plugin list which shows a warning
to the admin. This fix just prevents the broken link from rendering
in the sidebar if the route is not valid.
For plugins with only an "enabled" site setting, it doesn't
make sense to take them to the site settings page, since the
toggle switch in the list can be used to change enabled/disabled.
This will not be the case for plugins that have their own custom
config page (like Automation), but we will deal with this when
we actually overhaul this plugin to use the new show page.
Also adds another rspec fixture of a test plugin.
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.
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
