test flake: TestWebhookConverterWithWatchCache: wrong error on decode

Which jobs are flaking?

Integration testing (seen in ci-kubernetes-integration-arm64-1-37, ci-kubernetes-integration-1-37, etc., probably unfixed on master).

https://storage.googleapis.com/k8s-triage/index.html?text=TestWebhookConverterWithWatchCache%2Ffailure-message-v1#408ccc9147811eaffc9a

https://prow.k8s.io/view/gs/kubernetes-ci-logs/logs/ci-kubernetes-integration-arm64-1-37/2095070975300210688

RUN   TestWebhookConverterWithWatchCache/failure-message-v1/check-0/get
    conversion_test.go:841: expected error with message custom webhook conversion error, but got Internal error occurred: StorageError: corrupt object, Code: 7, Key: /stable.example.com/multiversion/webhook-conversion-failure-message-v1-check-0/failure-message, ResourceVersion: 0, AdditionalErrorMsg: object not decodable revision=400: conversion webhook for stable.example.com/v1beta1, Kind=MultiVersion failed: the server rejected our request due to an error in our request

https://storage.googleapis.com/k8s-triage/index.html?text=TestWebhookConverterWithWatchCache%2Ffailure-message-v1#ec65ff6904b4cfc26a13

https://prow.k8s.io/view/gs/kubernetes-ci-logs/logs/ci-kubernetes-integration-arm64-1-37/2093589448393494528

RUN   TestWebhookConverterWithWatchCache/failure-message-v1beta1/check-0/get
    conversion_test.go:839: expected error with message custom webhook conversion error, but got no error

Which tests are flaking?

TestWebhookConverterWithWatchCache

Since when has it been flaking?

Unknown.

Testgrid link

No response

Reason for failure (if possible)

No response

Anything else we need to know?

No response

Relevant SIG(s)

/sig api-machinery