switch disk timeout test to debian 10

[modular-magician]

switching test to use debian 10 as debian 11 seems to beat the timeout
https://ci-oss.hashicorp.engineering/buildConfiguration/GoogleCloud_ProviderGoogleCloudGoogleProject/322322?buildTab=tests&status=failed&expandedTest=6330899725422803853

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Derived from GoogleCloudPlatform/magic-modules#6383

[github-actions]

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