Change pixl schema so that it makes sense on multi-schema db

[stefpiatek]

We can't have it called pixl because for CI postgres doesn't like it when the database is the same name as the schema. So we had it as pipeline but that doesn't make sense on a shared database like the UDS.

Breaking change but no one else is using it so I think we can squeak this one through

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.61%. Comparing base (aa702e3) to head (0932d26).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #600   +/-   ##
=======================================
  Coverage   87.61%   87.61%           
=======================================
  Files          76       76           
  Lines        3505     3505           
=======================================
  Hits         3071     3071           
  Misses        434      434           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[milanmlft]

LGTM 👌