Ensure that ClickHouse CI tests run on CH 24 and CH 25 versions
Update the GitLab CI scripts to run the migration and backend tests with CH v24 and v25 (keep the existing v23).
This ensures that we're compatible with the latest ClickHouse version.
Additionally, document the supported versions in the integration guidelines: https://docs.gitlab.com/integration/clickhouse/
Edited by Adam Hegyi