[9.3] (backport #11892) handle curve_types to []curve_types conversion in beat es config

[mergify]

What does this PR do?

Allows ssl.curve_types to be a string as well as a slice of strings when translating beats elasticsearch configuration to otel elasticsearch exporter.

Why is it important?

Beats configuration for elasticsearch configuration allows for ssl.curve_types to be a string or slice of strings.

Checklist

• I have read and understood the pull request guidelines of this project.
• 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
• I have added an entry in ./changelog/fragments using the changelog tool
• I have added an integration test or an E2E test

Disruptive User Impact

How to test this PR locally

Related issues

• Relates change elasticsearch configuration DecodeHook function to handle string to []string #11732
• Closes [enhancement] Allow curve_type to be string or slice of string in elasticsearch config. #11776

Questions to ask yourself

• How are we going to support this in production?
• How are we going to measure its adoption?
• How are we going to debug this?
• What are the metrics I should take care of?
• ...

---

This is an automatic backport of pull request #11892 done by [Mergify](https://mergify.com).

[elasticmachine]

Pinging @elastic/elastic-agent-control-plane (Team:Elastic-Agent-Control-Plane)

[elasticmachine]

💔 Build Failed

• Buildkite Build
• Commit: 648d5d4

Failed CI Steps

• Win2022:sudo:standalone-upgrade
• Win2022:sudo:standalone-upgrade
• Win2022:sudo:upgrade-flavor
• Win2022:sudo:upgrade-flavor
• Win2025:sudo:standalone-upgrade
• Win2025:sudo:standalone-upgrade
• Win2025:sudo:upgrade-flavor
• Win2025:sudo:upgrade-flavor
• x86_64:sudo: upgrade-flavor
• x86_64:sudo: upgrade-flavor
• x86_64:sudo: standalone-upgrade
• x86_64:sudo: standalone-upgrade
• arm:sudo: upgrade-flavor
• arm:sudo: upgrade-flavor
• arm:sudo: standalone-upgrade
• arm:sudo: standalone-upgrade
• x86_64:sudo: upgrade-flavor - platform-ingest-elastic-agent-debian-11-1765760468
• x86_64:sudo: upgrade-flavor - platform-ingest-elastic-agent-debian-11-1765760468
• x86_64:sudo: upgrade-flavor - platform-ingest-elastic-agent-debian-13-1765760468
• x86_64:sudo: upgrade-flavor - platform-ingest-elastic-agent-debian-13-1765760468
• x86_64:sudo: standalone-upgrade - platform-ingest-elastic-agent-debian-11-1765760468
• x86_64:sudo: standalone-upgrade - platform-ingest-elastic-agent-debian-11-1765760468
• x86_64:sudo: standalone-upgrade - platform-ingest-elastic-agent-debian-13-1765760468
• x86_64:sudo: standalone-upgrade - platform-ingest-elastic-agent-debian-13-1765760468

History

cc @leehinman