For the admin plugin list we want to be able to link to
a meta topic for plugins, but we have no standard way to
do this at the moment. This adds support for meta_topic_id
alongside other plugin metadata like authors, URL etc,
that gets built into a Meta topic URL in the serializer.
This plugin is no longer supported, and so we no longer need to run its tests in CI
(removing the comment and the 'Canned Replies' value from the array caused syntax_tree to change to the `%w` syntax)
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.
