Fix the ignorance of DB version used in tests

[Shmuma]

As I discovered recently, --db-version parameter we set in github workflows is ignored and all the integration tests are running against the default ITDE DB version (8.18.1 at the moment).

This need to be fixed by passing the version via environment variable and use it on ITDE startup.
As long-term solution, we can migrate to pytest-plugins for all tests, but it might be done in a separate task