feat(cloudwatch): add search expression to graph widget in cloudwatch dashboard

[abidhasan-aws]

Issue # (if applicable)

Closes #7237

Reason for this change

Currently, GraphWidget only supports MathExpression or Metric objects. There is no native support for SearchExpression.
Although it is possible to use a search expression through a math expression, doing so requires hacky workarounds and additional boilerplate code.

Description of changes

AddedSearchExpression class to enable native support for search expression within GraphWidget.

Description of how you validated changes

Added unit tests and integration tests.

Checklist

• My code adheres to the CONTRIBUTING GUIDE and DESIGN GUIDELINES

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By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license

[aws-cdk-automation]

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[Abogical]

Thank you! Some changes are needed.

[Abogical]

You can use a scoped Validation Error in this context with the scope of the Alarm.

Suggested change

	withSearchExpression(_searchExpr, _conf) {
	throw new UnscopedValidationError('Search expressions are not supported in CloudWatch Alarms. Use search expressions only in dashboard graphs.');
	withSearchExpression: (_searchExpr, _conf) => { // Use arrow function to not override `this` from the class instance.
	throw new ValidationError('Search expressions are not supported in CloudWatch Alarms. Use search expressions only in dashboard graphs.', this);

[Abogical]

Scoped validation error here as well.

[Abogical]

You can also "hoist" the applyExpressionOptions function for cleaner code.

const applyExpressionOptions = (options: any, exprConfig: MetricExpressionConfig) => {
  ...
};

function metricGraphJson(metric: IMetric, yAxis?: string, id?: string) {
  ...
  withMathExpression(mathExpr) {
      applyExpressionOptions(options, mathExpr);
    },
    withSearchExpression(searchExpr) {
      applyExpressionOptions(options, searchExpr);

[aws-cdk-automation]

AWS CodeBuild CI Report

• CodeBuild project: AutoBuildv2Project1C6BFA3F-wQm2hXv2jqQv
• Commit ID: 0d1d4f9
• Result: SUCCEEDED
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[Abogical]

Thank you!