As mentioned in commits like a586ba806, a7664ad81, 006128da5, b41fbfa52
and c480cdd91, accessing the database after starting the browser with
the `visit` method sometimes results in database corruption and failing
tests on our CI due to the process running the test accessing the
database after the process running the browser has started.
Note that, in this case, in order to make the tests more readable, we're
adding a bit of duplication. We should probably simplify these tests by
moving most of the checks to mailer tests and then we could remove the
duplication. The alternative would be to make the
`create_direct_message` method way more complex than it is right now.
We're improving the readability of the ones we're about to modify.
Using human texts makes tests easier to read and guarantees we're
testing from the user's point of view. For instance, if we write
`fill_in banner_target_url`, the test will pass even if the field has no
label associated to it. However, `fill_in "Link"` makes sure there's a
field with an associated label.
