[lambda_logs] fix parsing failure when message is string

[gpop63]

Proposed commit message

this PR fixes lambda_logs parsing failure when aws.lambda.message receives a string value instead of an object.

Checklist

• I have reviewed tips for building integrations and this pull request is aligned with them.
• I have verified that all data streams collect metrics or logs.
• I have added an entry to my package's changelog.yml file.
• I have verified that Kibana version constraints are current according to guidelines.
• I have verified that any added dashboard complies with Kibana's Dashboard good practices

Author's Checklist

• [ ]

How to test this PR locally

Related issues

• Closes [aws]: Issue with AWS lambda logs in JSON format #15375

Screenshots

[gpop63]

/test

[elastic-vault-github-plugin-prod]

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[botelastic]

Hi! We just realized that we haven't looked into this PR in a while. We're sorry! We're labeling this issue as Stale to make it hit our filters and make sure we get back to it as soon as possible. In the meantime, it'd be extremely helpful if you could take a look at it as well and confirm its relevance. A simple comment with a nice emoji will be enough :+1. Thank you for your contribution!

[elasticmachine]

💚 Build Succeeded

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• Commit: 65e7df0

History

• 💚 Build #38166 succeeded c6bad33

cc @gpop63

[agithomas]

Could this be a breaking change? Please re-check.

[yavor-martian]

In which release can we expect this to land?

[yavor-martian]

@gpop63 could you please take a look at this one.

[gpop63]

Could this be a breaking change? Please re-check.

No field types are being changed here, just the way we check if its of type String or Map, the way we store values inside that field is changed.