saikatak

aws-qa-appsync-opensearch: Make congnito user pool id as optional input

1

### Describe the feature Currently the module [aws-qa-appsync-opensearch](https://github.com/awslabs/generative-ai-cdk-constructs/tree/main/src/patterns/gen-ai/aws-qa-appsync-opensearch) authenticates GraphQL APIs using cognito user as primary authentication mode and IAM as additional authentication mode. This module is requiring cognito user...