chore: fix monitoring test

[xeniape]

Description

Small follow-up PR to #955
The PR introduced additional monitoring testing, which was part of unreachable code and therefore wasn't tested. This fixes it.

--- PASS: kuttl (235.86s)
    --- PASS: kuttl/harness (0.00s)
        --- PASS: kuttl/harness/smoke_zookeeper-3.9.3_use-server-tls-false_use-client-auth-tls-false_openshift-false (133.77s)
        --- PASS: kuttl/harness/smoke_zookeeper-3.9.3_use-server-tls-true_use-client-auth-tls-false_openshift-false (151.03s)
        --- PASS: kuttl/harness/smoke_zookeeper-3.9.3_use-server-tls-false_use-client-auth-tls-true_openshift-false (86.24s)
        --- PASS: kuttl/harness/smoke_zookeeper-3.9.3_use-server-tls-true_use-client-auth-tls-true_openshift-false (84.81s)
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.
• Helm chart can be installed and deployed operator works
• Integration tests passed (for non trivial changes)
• Changes need to be "offline" compatible
• Links to generated (nightly) docs added
• Release note snippet added

Reviewer

• Code contains useful comments
• Code contains useful logging statements
• (Integration-)Test cases added
• Documentation added or updated. Follows the style guide.
• Changelog updated
• 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
• Links to generated (nightly) docs added
• Release note snippet added
• Add type/deprecation label & add to the deprecation schedule
• Add type/experimental label & add to the experimental features tracker

[dervoeti]

Minor nitpick, LGTM otherwise