fixes #6686 - Remove extraneous alch-alert div from CV filters index

Both the Content View and Content View Filters views have an alch-alert
div, which causes alerts to be shown twice in some situations.  The
Content View filters alch-alert is provided through the nutupane details
layout, and this PR provides a way to hide it.
Merge pull request #4457 from stbenjam/6686

fixes #6686 - remove extraneous alch-alert div from CV filters index