feat: VPC Endpoint support for COGNITO-IDP

[shkim4u]

• Add Cognito VPC Endpoint (Private Link) Support for Isolated Network Deployment Add Cognito VPC Endpoint (Private Link) Support for Isolated Network Deployment #703

Description of changes:

• package.json: "aws-cdk-lib": "^2.212.0" => "aws-cdk-lib": "^2.231.1", (To have ec2.InterfaceVpcEndpointAwsService.COGNITO_IDP)
• package-lock.json: Synced with package.json
• lib/shared/index.ts: Cognito IDP Endpoint
• tests/snapshots/cdk-app.test.ts.snap, tests/chatbot-api/snapshots/chatbot-api-construct.test.ts.snap: Updated test snapshot

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