Add ExceptionMessage to HealthCheck and sanitize data

[davidkallesen]

Summary

• Add ExceptionMessage property to the HealthCheck record
• Sanitize Exception objects in health check data to string messages
• Extend test coverage for exception handling and data sanitization

Changes

✨ Features

• Add ExceptionMessage property to HealthCheck record
• Map HealthReportEntry.Exception?.Message to ExceptionMessage
• Sanitize Exception objects in Data dictionary to their Message strings

✅ Tests

• Add test for exception message mapping on unhealthy checks
• Add test for Exception sanitization in Data dictionary
• Add test for preserving non-Exception objects in Data
• Add test for preserving ResourceHealthCheck in Data
• Update existing deconstruct tests for new ExceptionMessage field
• Add HealthCheckOptionsFactory tests

📝 Documentation

• Update generated API docs for new ExceptionMessage property