storage.api.server: Add types to module and refactor tests
- Refactor the tests to simplify the reading (use pytest.raises' match behavior)
- Add types on impacted functions so the coverage shows as well
Not really for review. Preparatory work to fix configuration discrepancy which is the source of the docker-dev error.
Test Plan
tox
Migrated from D4279 (view on Phabricator)