aws/config: fix null EvaluationResults crash in CEL program

[kcreddy]

Proposed commit message

aws/config: fix null EvaluationResults crash in CEL program

The GetComplianceDetailsByConfigRule AWS API can return
{"EvaluationResults": null} instead of an empty array when no
compliance results exist for a rule. The CEL program used
has(body.EvaluationResults) && size(body.EvaluationResults) > 0
to check for results, but has() returns true for null values and
size(null) has no overload in CEL, causing a runtime crash.

Add type(body.EvaluationResults) == list into the condition to 
safely handle both missing and null values.

Update the system test mock to return null EvaluationResults for
one config rule, covering this scenario.

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

How to test this PR locally

Added system test scenario passes.

[infra-vault-gh-plugin-prod]

Pinging @elastic/security-service-integrations (Team:Security-Service Integrations)

[efd6]

This looks like a dup of #18787.

Except I'm not convinced by the type check. Formally, this change here is more correct, but I think the change there is easier to read with approximately no additional risk.

[kcreddy]

This looks like a dup of #18787, but you were here first.

I like that you were also fixing in other places. Lets go with your change. I like that one. Thanks for flagging, I thought I fixed it already last week :(

Closing as duplicate of #18787

[elastic-vault-github-plugin-prod]

🚀 Benchmarks report

Package aws 👍(14) 💚(4) 💔(4)

Expand to view

Data stream	Previous EPS	New EPS	Diff (%)	Result
lambda_logs	11627.91	7874.02	-3753.89 (-32.28%)	💔
securityhub_insights	1652.89	1375.52	-277.37 (-16.78%)	💔
vpcflow	8771.93	6944.44	-1827.49 (-20.83%)	💔
ec2_logs	58823.53	40000	-18823.53 (-32%)	💔

To see the full report comment with /test benchmark fullreport

[elasticmachine]

💚 Build Succeeded

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• Commit: 2d43303

History

• 💔 Build #42174 failed cedb645

cc @kcreddy