Backport #37162 by @silverwind
When running `golangci-lint` without `GOEXPERIMENT=jsonv2`, a lint error
`import 'encoding/json' is not allowed` is seen.
All other files in the module that import `encodings/json` have
`//nolint` already, so add it.
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This PR was written with the help of Claude Opus 4.6
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Claude (Opus 4.6) <noreply@anthropic.com>