Fix results/query in api/v1/featured_tags/suggestions

[mjankowski]

The bug fix here is pulled from #28815 which found it as a side effect, but did not fully flesh out a spec to show the issue. Changes here:

• Remove the tag from the featured tag fabricator - this class sets this internally from the name of the tag
• Remove extraneous/unused account_id in params in the request spec
• Connect the account and user in request spec
• Add assertions about which tag is found in the results (the recently used but not featured one), verify this fails
• Update controller query to match tag ids with tag ids. The previous query was something like "where tag id is not in featured tags", but this was comparing against the id of the featuredtag records, not the tag_id connected to them.

Will rebase that other one after this, as I think this (and the other usage) would still read better as scopes.