Re add tiller namespace to helm commands

What does this MR do?

Add --tiller-namespace to helm commands used in review-apps.sh scripts. Without the namespace, the commands could get incorrect result. For example, helm status will not find a release that is in a --tiller-namespace=review-apps-ee.

This is a reopening of !19858 (diffs) which was reverted because Review App deployments were broken.

Does this MR meet the acceptance criteria?

Conformity

• Code review guidelines
• Merge request performance guidelines
• Style guides
• Separation of EE specific content

Availability and Testing

• Deployment works: https://gitlab.com/gitlab-org/gitlab/-/jobs/355118575
• Review App teardown works: https://gitlab.com/gitlab-org/gitlab/-/jobs/355242086

Related to #36022 (closed).