test fix for TestGetAddonRecommendations

[eviljeff]

Follow-up for: mozilla/addons#15377

Description

Trivial test fix for the TAAR removal PR. Not identified at the time due to mozilla/addons#15444

Testing

n/a

Checklist

• Add #ISSUENUM at the top of your PR to an existing open issue in the mozilla/addons repository.
• Successfully verified the change locally.
• The change is covered by automated tests, or otherwise indicated why doing so is unnecessary/impossible.
• Add before and after screenshots (Only for changes that impact the UI).
• Add or update relevant docs reflecting the changes made.

[eviljeff]

Added another commit that gets our tests back to green. Added to this PR because it's another connected fail from the TAAR removal, but in the weirdest way - we were mocking statsd in completely the wrong file for 3 years 🙃 - it always should have been olympia.devhub.utils rather than olympia.addons.utils.