Ingestion Controls: Agent Level configuration modal

[dussault-antoine]

What does this PR do?

Add documentation for the new Agent Level configuration modal JIRA Epic link

Motivation

Additional Notes

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Reviewer checklist

• [ ] Review the changed files.
• [ ] Review the URLs listed in the Preview section.
• [ ] Check images for PII
• [ ] Review any mentions of "Contact Datadog support" for internal support documentation.

[github-actions[bot]]

Preview links (active after the build_preview check completes)

New or renamed files

Removed or renamed files (these should redirect)

Modified Files

• https://docs-staging.datadoghq.com/antoine.dussault/ingestion_controls_agent_level_config/tracing/trace_pipeline/ingestion_controls

[kayayarai]

Opened DOCS-3921 to track edit pass