We had two different keys with the same text and were passing it as a
parameter. Since the text is the same in any case, we don't need a
parameter for it.
Note we are using the `proposals` i18n key instead of creating a new one
in a `shared` namespace one because creating a new key would mean that
we'd lose the already existing translations in Crowdin.
We were manually generating the IDs in order to pass them as data
attributes in the HTML in a component where we don't have access to the
form which has the inputs.
However, these data attributes only make sense when there's a form
present, so we can pass the form as a parameter and use it to get the
IDs.
We can now define a map as editable when there's an associated form,
which makes sense IMHO.
It was possible to remove a map location from a different proposal (even
one created by a different author) by modifying the hidden `id`
parameter in the form.
So we're making sure the map location we destroy is the one associated
to the proposal we're updating.
Since we're now using the `@proposal` instance variable in the
`destroy_map_location_association` method, we're calling that method
after loading the resource with cancancan.
Using the block syntax to generate the label with a <span> tag inside
isn't necessary after upgrading foundation_rails_helpers. Before the
upgrade, we couldn't do so because the <span> tag was escaped.
