[Website]: Update Use APM with OTel docs

[theletterf]

Type of issue

Inaccurate

What documentation page is affected

https://www.elastic.co/docs/solutions/observability/apm/use-opentelemetry-with-apm

What happened?

Diagrams and OTel related information on this page is outdated. Review and update.

+CC @davidgeorgehope @ty-elastic

Additional info

No response