ci: Push new s3-image when the openQA tests pass
This should have the following effects for CI pipelines on 'master':
- if the openQA tests (test-s3-image job) fails, the pipeline will be considered failed (currently it can succeed even if test-s3-image fails)
- if the openQA tests pass, the s3-image-static job will run to update the primary image on https://os.gnome.org.
There should be no changes for merge-request pipelines.
To consider, this means we will no longer be able to update the primary os.gnome.org image when the openQA tests fail.
Fixes #701 (closed)