enrich 'error.exception.type' for captured Elasticsearch client errors for better grouping

[trentm]

Description

To improve error grouping of captured Elasticsearch client errors, APM agents MAY enrich error.exception.type with the "error.type" value from the Elasticsearch response body JSON payload, if easily available.

• spec: https://github.com/elastic/apm/blob/main/specs/agents/tracing-instrumentation-db.md#elasticsearch
• spec PR: https://github.com/elastic/apm/pull/653

The Node.js APM agent implemented this here: https://github.com/elastic/apm-agent-nodejs/issues/2770

Agent Issues

• [ ] https://github.com/elastic/apm-agent-java/issues/2742
• [ ] https://github.com/elastic/apm-agent-dotnet/issues/1783
• [ ] https://github.com/elastic/apm-agent-python/issues/1611
• [ ] https://github.com/elastic/apm-agent-go/issues/1296
• [ ] https://github.com/elastic/apm-agent-php/issues/744
• [ ] https://github.com/elastic/apm-agent-ruby/issues/1295