Update monitoring (CloudWatch) endpoints to match AWS

[trgoodwin]

• Add missing regions to the monitoring service endpoints: af-south-1, ap-east-2, ap-northeast-3, ap-southeast-3, ap-southeast-4, ap-southeast-5, ap-southeast-6, ap-southeast-7, ca-west-1, eu-central-2, eu-south-1, eu-south-2, il-central-1, me-central-1, mx-central-1
• Sort entries alphabetically for consistency

Endpoints verified against the https://github.com/aws/aws-sdk-go-v2/blob/main/codegen/smithy-aws-go-code
gen/src/main/resources/software/amazon/smithy/aws/go/codegen/endpoints.json