fix: allow multiple events in a cwl event

[alemairebe]

This change allow the use of 'delimiters' in addition to cloudwatch logs events split. In my case, it is useful to get SecurityHub Findings via CloudWatch Logs. https://docs.aws.amazon.com/securityhub/latest/userguide/securityhub-cwe-all-findings.html My current customer did that setup following an LAZ guideline.

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[alemairebe]

Main difference versus the 2 others PRs about this is the use of value_from_nesteddict_by_dottedkey to allow to get json_delimiter = detail.findings instead of json_delimiter = findings