test: update tests for envOverrides

[razvan]

Description

Part of : stackabletech/issues#548

🟢 Test:

--- PASS: kuttl (147.39s)
    --- PASS: kuttl/harness (0.00s)
        --- PASS: kuttl/harness/smoke_hadoop-3.4.0_zookeeper-3.9.2_zookeeper-latest-3.9.2_number-of-datanodes-2_datanode-pvcs-2hdd-1ssd_listener-class-external-unstable_openshift-false (147.37s)
PASS

Definition of Done Checklist

• Not all of these items are applicable to all PRs, the author should update this template to only leave the boxes in that are relevant
• Please make sure all these things are done and tick the boxes

# Author
- [ ] Changes are OpenShift compatible
- [ ] CRD changes approved
- [ ] CRD documentation for all fields, following the [style guide](https://docs.stackable.tech/home/nightly/contributor/docs/style-guide).
- [ ] Helm chart can be installed and deployed operator works
- [ ] Integration tests passed (for non trivial changes)
- [ ] Changes need to be "offline" compatible

# Reviewer
- [ ] Code contains useful comments
- [ ] Code contains useful logging statements
- [x] (Integration-)Test cases added
- [ ] Documentation added or updated. Follows the [style guide](https://docs.stackable.tech/home/nightly/contributor/docs/style-guide).
- [ ] Changelog updated
- [x] Cargo.toml only contains references to git tags (not specific commits or branches)

# Acceptance
- [ ] Feature Tracker has been updated
- [ ] Proper release label has been added
- [ ] [Roadmap](https://github.com/orgs/stackabletech/projects/25/views/1) has been updated

[adwk67]

LGTM