Wait for CNG instead of Helm packager pipeline

What does this MR do and why?

Describe in detail what your merge request does and why.

Wait for the CNG packager pipeline instead of the Helm pipeline, before continuing the rest of the auto-deploy pipeline.

Testing:

1. I created this test pipeline to make sure that the pipeline definition is fine: https://ops.gitlab.net/gitlab-org/release/tools/-/pipelines/1355866.
2. I ran ReleaseTools::AutoDeploy::WaitForPackage.new(ReleaseTools::Project::CNGImage, ReleaseTools::Project::CNGImage.metadata_project_name).execute in a pry session, which correctly waited for the latest CNG pipeline to complete.

gitlab-com/gl-infra/delivery#2493 (closed)

Author Check-list

• Has documentation been updated?