Label needed for "What's new? post in" select on News Feed

[MartinPaulEve]

Moved from MESH-Research/knowledge-commons-profiles#380 (originally by @gmeben)

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

Description
The select dropdown (<select id="whats-new-post-in" name="whats-new-post-in">) that appears when the "What's new, ___?" is focused does not have a label.

Recommendation

Any one of these should fix the issue:

1. Change the name attribute of the select to an id, refactor the markup of the label from a <span> to a <label>, and add a for="whats-new-post-in" attribute to the label
2. Add a title attribute to the select
3. Add an aria-label attribute to the select