Fixes for test flakes (backport #12671) (backport #12672)

[mergify]

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This is an automatic backport of pull request #12671 done by [Mergify](https://mergify.com).

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This is an automatic backport of pull request #12672 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of 4d194b7 has failed:

On branch mergify/bp/v3.13.x/pr-12672
Your branch is ahead of 'origin/v3.13.x' by 1 commit.
  (use "git push" to publish your local commits)

You are currently cherry-picking commit 4d194b7411.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   deps/rabbitmq_management/test/clustering_prop_SUITE.erl

no changes added to commit (use "git add" and/or "git commit -a")

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally