Currently origin_metadata_add endpoints will fail with the following [1] error
trying to insert dict into a bytea field.

tl;dr the tests currently send the right input of bytes but the code in prod
sends dict. Which should be mapped to bytes, but a jsonize calls transforms
it into the previous jsonb format.

[1] https://sentry.softwareheritage.org/share/issue/5ef4e31eaa3847a4a23e39847c9ac55f/