/consultations retains query params when redirecting

Zendesk: https://govuk.zendesk.com/agent/#/tickets/612037

The consultations controller index action redirects onto the publications controller setting publication_filter_option=consultations.  There are links which use the consultations_path helper adding  in pre-set filter values.  These were getting dropped by the redirect.

For an example, see the "See all consultations" link on a topic page (https://www.gov.uk/government/topics/public-health).  The link takes the user to the publications index showing all consultations instead of only consultations related to that topic.