We're going to add some JavaScript which affect this component, and IMHO
it will be easier to know the JavaScript affects this form if both have
their own separate file.
We have three filters: "pending", "all" and "reviewed". Where "pending"
is the default one.
Now we are rendering the `shared/_filter_subnav` partial we need to stub
helper methods defined at the controller and the helper methods that
rely on the request parameters to test the component.
Note using `params[:relatable_type].classify` is recognized as a
security risk by some tools. However, it's a false positive, since we've
added constraints to the URL so that paramenter can only have the values
we trust.
