refactor: use builder pattern for CallToolResult and simplify lambda expressions in tests

[codeboyzhou]

What's Changed

1. Use builder pattern for CallToolResult to replace deprecated method usages.
2. Replace some lambda expressions with method reference to simplify code.
3. Fix a typo in class AbstractMcpClientServerIntegrationTests.

Motivation and Context

Simplify code and improve readability.

How Has This Been Tested?

Just run the tests because there is no logic changes.

Breaking Changes

No.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

No.