Our enboarding in Konflux was made with x86_64 only, we need to enable s390x builds.

This requires changing the pipeline we use from single-arch to multi-arch, then enabling the additional platform.

See documentation:
https://konflux.pages.redhat.com/docs/users/getting-started/multi-platform-builds.html
https://konflux.pages.redhat.com/docs/users/building/reconfiguring-build-pipeline.html#changing-pipelines

Note: the bundle image doesn't need to be mutlti-arch.