When this code was added, in commit 1a20a3ce4, we had no validation
rules checking the presence of the start and end dates of a poll. Now we
do, so we don't have to check this condition in the view.
We were using a redundant `elsif` instead of an `else`. We were also
using a negative condition in the main `if`, which made the code a bit
harder to read.
Since we usually use `current_user` instead of `user_signed_in?`, we're
also changing that for consistency.Extract component to render the status of a poll
This is consistent with the way we've got partials to render debates,
proposals and legislation processes on their index pages.
Note that, while adding the tests for the status icon, we're keeping one
system test because it also tests the process of voting. We're adding a
new, similar component test, where the voter is created in the database,
so all possible statuses are tested in the component.
