Label needed on "Activity filter" select on News Feed

[MartinPaulEve]

Moved from MESH-Research/knowledge-commons-profiles#379 (originally by @gmeben)

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Area of site: News Feed
URL: https://hcommons-staging.org/activity/

Description
The "activity filter" select (<select id="activity-filter-by">) does not have a label.

Recommendation

Either one of these will fix the issue:

1. Add a title attribute to the select
2. Add an aria-label attribute to the select