Upgrade System.Linq.Dynamic.Core to 1.6.0 and fix breaking changes

[Copilot]

This PR upgrades System.Linq.Dynamic.Core from version 1.3.0 to 1.6.0 to address the high severity security vulnerability GHSA-4cv2-4hjh-77rx.

Problem

The current version 1.3.0 has a known security vulnerability that needs to be resolved. However, upgrading to 1.6.0 introduces breaking changes due to stricter security controls that prevent access to certain .NET framework methods like object.Equals() used in workflow definitions.

Solution

1. Expression Transformation

Added automatic transformation of legacy expression patterns to maintain backward compatibility:

// Before (fails in 1.6.0)
"object.Equals(data[\"Flag1\"], true)"

// After (automatically transformed)
"Convert.ToBoolean(data[\"Flag1\"]) == true"

2. Enhanced Security Configuration

Implemented a ParsingConfig with appropriate permissions for workflow expression parsing while maintaining security:

private static readonly ParsingConfig ParsingConfig = new ParsingConfig
{
    AllowNewToEvaluateAnyType = true,
    AreContextKeywordsEnabled = true
};

3. Comprehensive Updates

Updated all DynamicExpressionParser.ParseLambda() calls throughout the DefinitionLoader to use the new configuration and automatic expression transformation.

Backward Compatibility

Existing workflow definitions continue to work without modification:

• JSON and YAML workflow files with object.Equals() expressions are automatically converted
• No breaking changes for end users
• All existing functionality preserved

Testing

Verified the upgrade works correctly with:

• Existing test asset definitions (stored-dynamic-definition.json/yaml)
• Simple dynamic property access expressions
• Complex conditional expressions with equality comparisons
• Both JSON and YAML workflow definition formats

The security vulnerability warning is now resolved, and the build produces no vulnerability warnings.

Fixes #1371.

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