Only pass visible pages to ConfigPagesView template
Review Request #9984 — Created May 25, 2018 and submitted
The ConfigPagesView was passing all pages, regardless of visibility,
to the template, which then filtered out invisible pages. Instead, we
now filter out before passing the pages to the template (which also
means instantiating less forms since we aren't instantiating forms for
pages that won't render).
Ran unit tests.