[release-4.16] NO-JIRA: only update envvar listeners on real changes

[Elbehery]

While reviewing the changes in the backup PR, I've seen that I've introduced unnecessary listener updates during the lock refactoring two years ago.

This PR ensures we return early when the envvars has not changed.

Manual cherrypick of https://github.com/openshift/cluster-etcd-operator/pull/1300

[openshift-ci-robot]

@Elbehery: This pull request explicitly references no jira issue.

In response to [this](https://github.com/openshift/cluster-etcd-operator/pull/1302): >While reviewing the changes in the backup PR, I've seen that I've introduced unnecessary listener updates during the lock refactoring two years ago. > >This PR ensures we return early when the envvars has not changed. > >Manual cherrypick of https://github.com/openshift/cluster-etcd-operator/pull/1300 Instructions for interacting with me using PR comments are available [here](https://prow.ci.openshift.org/command-help?repo=openshift%2Fcluster-etcd-operator). If you have questions or suggestions related to my behavior, please file an issue against the [openshift-eng/jira-lifecycle-plugin](https://github.com/openshift-eng/jira-lifecycle-plugin/issues/new) repository.

[openshift-ci[bot]]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Elbehery

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/openshift/cluster-etcd-operator/blob/release-4.16/OWNERS)~~ [Elbehery] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[Elbehery]

/cherrypick release-4.15

[openshift-cherrypick-robot]

@Elbehery: once the present PR merges, I will cherry-pick it on top of release-4.15 in a new PR and assign it to you.

In response to [this](https://github.com/openshift/cluster-etcd-operator/pull/1302#issuecomment-2253156996): > >/cherrypick release-4.15 > > Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes-sigs/prow](https://github.com/kubernetes-sigs/prow/issues/new?title=Prow%20issue:) repository.

[Elbehery]

/retest-required

[Elbehery]

/retest-required

[openshift-ci[bot]]

@Elbehery: all tests passed!

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Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes-sigs/prow](https://github.com/kubernetes-sigs/prow/issues/new?title=Prow%20issue:) repository. I understand the commands that are listed [here](https://go.k8s.io/bot-commands).

[Elbehery]

/assign @tjungblu

[Elbehery]

/close

[openshift-ci[bot]]

@Elbehery: Closed this PR.

In response to [this](https://github.com/openshift/cluster-etcd-operator/pull/1302#issuecomment-2255382441): >/close Instructions for interacting with me using PR comments are available [here](https://git.k8s.io/community/contributors/guide/pull-requests.md). If you have questions or suggestions related to my behavior, please file an issue against the [kubernetes-sigs/prow](https://github.com/kubernetes-sigs/prow/issues/new?title=Prow%20issue:) repository.