[exporter/elasticsearch] data loss due to incorrect metrics grouping

[carsonip]

Component(s)

exporter/elasticsearch

What happened?

Description

Metrics: in OTel mapping mode, data points are not grouped properly and may result in validation error within ES exporter. Regression from #37509 released in 0.119.0

Steps to Reproduce

create 2 data points from different resources but ends up in the same index

Expected Result

No error

Actual Result

validation error

2025-02-13T08:14:29.974Z	warn	[email protected]/exporter.go:340	validation errors	{"kind": "exporter", "data_type": "metrics", "name": "elasticsearch/otel", "error": "metric with name 'k8s.node.condition_ready' has already been serialized in document with timestamp 2025-02-13T08:14:29.902238381Z\nmetric with name 'k8s.node.condition_memory_pressure' has already been serialized in document with timestamp 2025-02-13T08:14:29.902238381Z\nmetric with name 'k8s.node.condition_ready' has already been serialized in document with timestamp 2025-02-13T08:14:29.902238381Z\n

Collector version

0.119.0

Environment information

Environment

OS: (e.g., "Ubuntu 20.04")
Compiler(if manually compiled): (e.g., "go 14.2")

OpenTelemetry Collector configuration

Log output

Additional context

No response

[carsonip]

/label -needs-triage

[github-actions]

Pinging code owners:

• exporter/elasticsearch: @JaredTan95 @carsonip @lahsivjar

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