Ensure namespace exists in Kubernetes cluster

What does this MR do?

This fixes #118598 (closed).

Validated by https://staging.gitlab.com/hello-staging/hello-staging-cluster-management/-/jobs/36981038 succeeding

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.