Cherry-pick #16348 to 7.x: Fix loading processors from autodiscover hints

[blakerouse]

Cherry-pick of PR #16348 to 7.x branch. Original message:

What does this PR do?

Fixes an issue where processors from autodiscover hints where not convered into a common.MapStr.

Why is it important?

Allows processors to be defined in autodiscover hints.

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

Author's Checklist

• Converts string to common.MapStr

How to test this PR locally

Run filebeat with:

filebeat.autodiscover:
  providers:
    - type: docker
      hints.enabled: true

output.console:
  pretty: true

Start container with processor:

docker run -l 'co.elastic.logs/processors.add_fields={"fields":{"foo":"bar"}}' busybox echo hello

Check that filebeat was able to start logging it the container with the fields added.

Related issues

• Closes [Filebeat] Autodiscovery logs.processors does not convert string into a MapStr #16343

Use cases

Screenshots

Logs