elasticsearchexporter support for dynamic log Body json parsing

[PowerSurj]

Component(s)

exporter/elasticsearch

Is your feature request related to a problem? Please describe.

elasticsearchexporter doesn't do dynamic log Body json parsing without defining the Body schema.

When using transform processor merge_maps(cache, ParseJSON(body), "upsert") where IsMatch(body, "^\{")
all keys being prepended to attributes key.

However, we need to keep log message json keys to be at the root

Describe the solution you'd like

support dynamic nested json log message parsing in the exporter
resulting with the fields at the root document level without attributes. prefix

Describe alternatives you've considered

ELK Ingestion Pipelines can handle this, but it is an additional configuration dependency

Additional context

No response

[github-actions]

Pinging code owners:

• exporter/elasticsearch: @JaredTan95 @carsonip @lahsivjar

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