Do not try to push images on registry when disabled

Summary

At the moment, the GitLab Runner images published on the AWS ECR registry have been deactivated (PUSH_TO_ECR_PUBLIC: false). However, the CI still tries to push to images resulting in the failure of the related job as it can be seen in the Release stage of those pipelines (bleeding edge helper docker images jobs):

• https://gitlab.com/gitlab-org/gitlab-runner/-/pipelines/588444776
• https://gitlab.com/gitlab-org/gitlab-runner/-/pipelines/588395208

Steps to reproduce

Run the bleeding edge helper docker images jobs in the Release stage.

Actual behavior

The CI tries to push the images on the registry despite PUSH_TO_ECR_PUBLIC being set to false and fails, failing the whole pipeline when the ECR

Expected behavior

The CI should not try to push the images on the registry

Relevant logs and/or screenshots

NA

Environment description

NA

Used GitLab Runner version

GitLab Runner 15.1

Possible fixes