This way we remove a bit of duplication.
These changes also affect the way geozones are rendered in a couple of
minor ways, making them more consistent:
* No empty list of geozones is rendered when there are no geozones
(before these changes, an empty list was rendered in the index action
but not in the show action)
* The text clarifying the geozone restriction is always shown (before
these changes, it was shown in the index action but not in the show
action)
We've added tests for these cases.
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.
