Remove popularity from search index.

[isoos]

• Follow-up to Remove popularity from the UI, finalize download counts experiment. #8435.
• The sort value is not removed for now, we could probably keep it for a while, in case somebody bookmarked it.

[sigurdm]

I guess we could forward the old popularity searches to search ranked by download counts if we want to preserve old links.

Alternatively they could go to the generic ranking.

[isoos]

I guess we could forward the old popularity searches to search ranked by download counts if we want to preserve old links.

If you do https://pub.dev/packages?sort=x it will use the default sort order. So maybe what we need here is to canonicalize the search URLs and when we get a non-canonical one, we redirect to it. We already have parts of the redirect in place, maybe we just need to extend it.

[sigurdm]

If you do https://pub.dev/packages?sort=x it will use the default sort order.

I think that is good enough. Let's just remove the popularity one then. Old links would still lead to some search result.