Multiarch integration tests only selects one arch for charmhub release

[yanksyoon]

When given multi-arch integration tests, e.g. https://github.com/canonical/github-runner-image-builder-operator/actions/runs/12131525331/job/33831371303?pr=26
Only one (either AMD64 or ARM64 in this case) is released to CharmHub.
We would preferably have all the architectures within the integration tests be uploaded to charmhub.

[yanksyoon]

Created ticket: https://warthogs.atlassian.net/browse/ISD-2806