* Alerting: Add expression type to webhook valueString
- Add Type field to NumberValueCapture struct
- Implement AlertQuery.GetExpressionType() method
- Update valueString format to include type information
* Alerting: Add expression type to webhook valueString
- Fix tests
* Alerting: Add expression type to webhook valueString
- Update default annotations in notifier templates to include type field
* Alerting: Add expression type to webhook valueString
- Add type='math' to webhook and email test expectations