Remove full instance test suite execution from omnibus pipeline
What does this MR do and why?
Remove full test suite execution in omnibus pipelines. This adds unnecessary duplication and compute costs given full suite is executed by both gdk and cng pipelines.
References
Closes Change `e2e:test-on-omnibus-ee` Tier-3 to run s... (gitlab-com/gl-infra/delivery#21285 - closed)
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