fix HTTP 409 flake in AKS Cluster Class test

[nojnhuh]

What type of PR is this?
/kind flake

What this PR does / why we need it: This PR fixes a flake in the AKS e2e test where the Cluster Class test can get stuck trying to update an out-of-date version of the Cluster object and continuously hitting HTTP 409 errors by adding a GET in the retry loop before the update.

Here's one instance of the flake: https://prow.k8s.io/view/gs/kubernetes-jenkins/logs/periodic-cluster-api-provider-azure-e2e-aks-main/1743360260954918912

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #

Special notes for your reviewer:

• cherry-pick candidate

TODOs:

• squashed commits
• includes documentation
• adds unit tests

Release note:

NONE

[nojnhuh]

/cherry-pick release-1.12

[k8s-infra-cherrypick-robot]

@nojnhuh: once the present PR merges, I will cherry-pick it on top of release-1.12 in a new PR and assign it to you.

In response to this:

/cherry-pick release-1.12

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (1c7c802) 61.96% compared to head (715f3dc) 61.95%.
Report is 8 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4438      +/-   ##
==========================================
- Coverage   61.96%   61.95%   -0.02%     
==========================================
  Files         188      188              
  Lines       18768    18768              
==========================================
- Hits        11630    11628       -2     
- Misses       6500     6502       +2     
  Partials      638      638              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[nojnhuh]

/retest

[CecileRobertMichon]

/assign @willie-yao

[willie-yao]

/lgtm

Thanks for fixing this!

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 8f4053e288d25518465324821d1bfbb97fce3cc5

[nojnhuh]

/assign @CecileRobertMichon

[CecileRobertMichon]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: CecileRobertMichon

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• OWNERS [CecileRobertMichon]

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[k8s-infra-cherrypick-robot]

@nojnhuh: new pull request created: #4445

In response to this:

/cherry-pick release-1.12

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.