Update README.md

[LutaoX]

Updated link to public documentation for OTel datadog exporter and OTLP ingest. More specifically, instead of pointing to the generic link: https://docs.datadoghq.com/tracing/setup_overview/open_standards/#otlp-ingest-in-datadog-agent Datadog Exporter is pointing to: https://docs.datadoghq.com/tracing/setup_overview/open_standards/otel_collector_datadog_exporter/ OTLP ingest is pointing to: https://docs.datadoghq.com/tracing/setup_overview/open_standards/otlp_ingest_in_the_agent/

What does this PR do?

Motivation

Additional Notes

Review checklist (to be filled by reviewers)

• [ ] Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• [ ] PR title must be written as a CHANGELOG entry (see why)
• [ ] Files changes must correspond to the primary purpose of the PR as described in the title (small unrelated changes should have their own PR)
• [ ] PR must have changelog/ and integration/ labels attached

[sarah-witt]

Can this PR be closed in favor of https://github.com/DataDog/integrations-core/pull/12423/files?

[FlorentClarret]

Closing in favour of https://github.com/DataDog/integrations-core/pull/12423