db:migrate:multi-version-upgrade: Silence stdout `psql` when import SQL

The following discussion from !145432 (merged) should be addressed:

• @splattael started a discussion:

  Suggestion (non-blocking) While reviewing https://gitlab.com/gitlab-org/gitlab/-/jobs/6226975975#L912 I noticed that psql echos all input to stdout which contributes to the majority of the trace log size (14k lines).

  Should we silence the out of psql to reduce the trace size? 🤔

  If so, let's do this in a follow-up 💪