These settings are enabled by default.
It could be argued explicitely enabling the features makes tests more
consistent, because they'll work if we change the default setting. It
could also be argued that it makes tests more expressive because it
makes the reader realize certain things will only work if a setting is
enabled.
However, we were only doing so in a few tests. The truth is, thousands
of our tests depend on certain features being enabled. So IMHO we should
be consistent and either set them on every test, or not at all. I'm
choosing the latter option for simplicity.
Settings are stored in the database, and so any changes to the settings
done during the tests are automatically rolled back between one test and
the next one.
There were also a few places where we weren't using an `after` block but
changing the setting at the end of the test.
The `type: :feature` is automatically detected by RSpec because these
tests are inside the `spec/features` folder. Using `feature` re-adds a
`type: :feature` to these files, which will result in a conflict when we
upgrade to Rails 5.1's system tests.
Because of this change, we also need to change `background` to `before`
or else these tests will fail.
