Unwrap SQLAlchemy IntegrityErrors

[di]

Turns:

IntegrityError: ["raised as a result of Query-invoked autoflush; consider using a session.no_autoflush block if this flush is occurring prematurely"]

into something like:

psycopg.errors.NotNullViolation: null value in column "issuer_url" of relation "gitlab_oidc_publishers" violates not-null constraint
DETAIL:  Failing row contains (3e57929c-9437-4a0f-bca1-0bdb175d8821, foo/bar, baz, .gitlab-ci.yml, x, null).