[aws-cloudwatch] Add missing alarm comparison operators

[qmg-rbass]

Add missing alarm comparison operators GreaterThanUpperThreshold and LessThanLowerThreshold as per: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-properties-cw-alarm.html#cfn-cloudwatch-alarms-comparisonoperator

Use Case

For anomaly detection alarms

Proposed Solution

Add new enum values to ComparisonOperator

Other

• 👋 I may be able to implement this feature request
• ⚠️ This feature might incur a breaking change

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This is a 🚀 Feature Request