fix: instrumentation http needs required attributes

[victordrnd]

Summary

According to https://github.com/open-telemetry/opentelemetry-specification/blob/v1.20.0/specification/trace/semantic_conventions/http.md

The Opentelemetry "http.method" attribute is required to match an HTTP span. This allows to resolve the dependencies tree in Elastic APM by completing the span.destination.service.name field.

Checklist

• The Pull Request has tests
• A changelog file has been created under changelog/unreleased/kong or skip-changelog label added on PR if changelog is unnecessary. README.md

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[victordrnd]

Seems related to #14381