[APM][Otel] Ensure Errors views works with OTel data

[AlexanderWert]

We want to show the error views using Otel data. After the first steps to use fields instead of _source in our queries are done we want to make sure that the errors load correctly.
Currently, we see an error because some fields are missing (like handled) in this example

Technical details

To test with only Otel data go to APM settings and change all indices to otel

Run the PoC demo (make sure to stop all Kibana/ES instances (if any) running locally)
To use Kibana locally stop the Kibana Docker container and run your local Kibana

The missing error fields are a known issue:

• [enrichments] Add exception based enrichment for span events opentelemetry-lib#86

And it should be fixed first before working on it

AC:

• All error views in APM should work with Otel data
• All error views in APM should work with APM server (regression test)
• All tests should pass

[rmyz]

This will be merged on #195242