remove 'typecheck' linter because it's always enabled

[alexandear]

This PR removes redundant typecheck from the linters.enable list.

typecheck is not a linter and it doesn't perform any analysis. It's just a way to identify, parse, and display compiling errors and some linter errors.

More info:

• https://golangci-lint.run/welcome/faq/#why-do-you-have-typecheck-errors
• https://golangci-lint.run/welcome/faq/#why-is-it-not-possible-to-skipignore-typecheck-errors

[istio-testing]

Hi @alexandear. Thanks for your PR.

I'm waiting for a istio member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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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-sigs/prow repository.