Cannot seem to add a custom parser to the parsers conf of fluentd

The following error appears when starting fluentd. It continues to start up fine however it does not seem to continue to configure any custom parsers that come after it.

```
[2023/06/21 15:18:14] [error] [parser:container_firstline] Invalid regex pattern (?(?<="log":")\S(?!\.).*?)(?(?<="stream":").*?)".*(?\d{4}-\d{1,2}-\d{1,2}T\d{2}:\d{2}:\d{2}\.\w*).*(?=})
```

It seems to be configured here https://github.com/aws-samples/amazon-cloudwatch-container-insights/blob/main/k8s-deployment-manifest-templates/deployment-mode/daemonset/container-insights-monitoring/fluent-bit/fluent-bit.yaml#L229

Inspect fluent-bit/fluent-bit.yaml at the configuration around line 229 and compare it with the logged invalid regex pattern. Verify the parser configuration against Fluent Bit's accepted regex syntax and confirm that subsequent custom parsers are configured after the error is resolved.

Written by the indexing model from the issue text.