[internal/datadog] migrate hostmetadata package to datadog-agent/pkg/gohai

[jackgopack4]

Component(s)

internal/datadog

Describe the issue you're reporting

Currently, internal/datadog/hostmetadata/gohai imports github.com/DataDog/gohai packages.

This package was migrated to github.com/DataDog/datadog-agent-pkg/gohai and the original codebase was "archived" for compatibility/posterity.

As such, the references to this package should be updated to the datadog-agent repository to make sure we receive the latest feature updates and security patches.

This could also fix an odd issue where debug level logs appear in the collector of the format 1750257633929238000 [Debug] Process with pid 94870 disappeared while scanning: %!w(*errors.errorString=&{process does not exist}) on startup, not properly passed to the collector logging component.

[github-actions]

Pinging code owners:

• internal/datadog: @mx-psi @dineshg13 @liustanley @songy23 @mackjmr @ankitpatel96 @jade-guiton-dd @IbraheemA

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[jackgopack4]

May require upgrading github.com/DataDog/opentelemetry-mapping-go as well, not sure.