[8.19](backport #47693) [beatreceiver] Do not require specifiying otelconsumer output

[mergify]

Proposed commit message

All beatreceivers will use otelconsumer output by default and it does not require us to specify this explicitly.

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files
• I have added tests that prove my fix is effective or that my feature works. Where relevant, I have used the stresstest.sh script to run them under stress conditions and race detector to verify their stability.
• I have added an entry in ./changelog/fragments using the changelog tool.

Disruptive User Impact

None

Related issues

• Relates [beats receivers] Do not require explicit configuration of the otelconsumer output #47656

---

This is an automatic backport of pull request #47693 done by [Mergify](https://mergify.com).

[mergify]

Cherry-pick of b80d1e9 has failed:

On branch mergify/bp/8.19/pr-47693
Your branch is up to date with 'origin/8.19'.

You are currently cherry-picking commit b80d1e914.
  (fix conflicts and run "git cherry-pick --continue")
  (use "git cherry-pick --skip" to skip this patch)
  (use "git cherry-pick --abort" to cancel the cherry-pick operation)

Changes to be committed:
	modified:   x-pack/filebeat/fbreceiver/receiver_leak_test.go
	modified:   x-pack/filebeat/tests/integration/otel_test.go
	modified:   x-pack/libbeat/cmd/instance/beat_test.go
	modified:   x-pack/libbeat/common/otelbeat/oteltestcol/collector_test.go
	modified:   x-pack/metricbeat/mbreceiver/receiver_leak_test.go
	modified:   x-pack/metricbeat/mbreceiver/receiver_test.go
	modified:   x-pack/metricbeat/tests/integration/otel_test.go
	modified:   x-pack/otel/processor/beatprocessor/README.md
	modified:   x-pack/otel/processor/beatprocessor/integration_test.go

Unmerged paths:
  (use "git add/rm <file>..." as appropriate to mark resolution)
	both modified:   x-pack/filebeat/fbreceiver/receiver_test.go
	deleted by us:   x-pack/filebeat/tests/integration/otel_lsexporter_test.go
	both modified:   x-pack/libbeat/cmd/instance/beat.go

To fix up this pull request, you can check it out locally. See documentation: https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/reviewing-changes-in-pull-requests/checking-out-pull-requests-locally

[elasticmachine]

Pinging @elastic/elastic-agent-data-plane (Team:Elastic-Agent-Data-Plane)

[pierrehilbert]

@khushijain21 could you please fix the conflict?

[mergify]

This pull request has not been merged yet. Could you please review and merge it @khushijain21? 🙏