docs(prometheus): fix the description of some metrics

[johnfitzpatrick]

I believe a number of Prometheus plugin configs are described incorrectly.

Summary

The description for status_code_metrics, latency_metrics, bandwidth_metrics, and upstream_health_metrics

"A boolean value that determines if status code metrics should be collected"

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
• There is a user-facing docs PR against https://github.com/Kong/docs.konghq.com - PUT DOCS PR HERE

Issue reference

Fix #[issue number]

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Successfully created cherry-pick PR for master:

• https://github.com/kong/kong-ee/pull/8691