Remove SLES packages from auto-deploy builds

What does this MR do?

It was observed recently that for GitLab.com deploy builds we started building SLES packages. GitLab.com doesn't use that, so it is an unnecessary cost. Example pipeline https://dev.gitlab.org/gitlab/omnibus-gitlab/-/pipelines/191868

Testing

I've done testing for the following cases:

Autodeploy for GitLab.com

Used tag 13.11.202104012050+701c618a2ee.8cae629ba23

Self-managed tag EE build

Used tag 13.10.2+ee.0

Self-managed tag CE build

Used tag 13.10.2+ce.0

Self-managed RC tag EE build

Used tag 13.10.0+rc42.ee.0

Self-managed RC tag CE build

Used tag 13.10.0+rc42.ce.0

Branch build

Regular branch, without ee-variables

Branch with ee=true set

Related issues

Checklist

See Definition of done.

For anything in this list which will not be completed, please provide a reason in the MR discussion

Required

• Merge Request Title, and Description are up to date, accurate, and descriptive
• MR targeting the appropriate branch
• MR has a green pipeline on GitLab.com
• Pipeline is green on dev.gitlab.org if the change is touching anything besides documentation or internal cookbooks
• trigger-package has a green pipeline running against latest commit

Expected (please provide an explanation if not completing)

• Test plan indicating conditions for success has been posted and passes
• Documentation created/updated
• Tests added
• Integration tests added to GitLab QA
• Equivalent MR/issue for the GitLab Chart opened