Add comprehensive tests for WebSocketClientTransport

[HoberMin]

Description

This PR implements comprehensive tests for the WebSocketClientTransport class to ensure reliable WebSocket communication. The test suite covers connection establishment, failure handling, message processing, and protocol negotiation.

Key changes:

• Add mock WebSocket implementation for Node.js testing environment
• Test WebSocket connection establishment and closure
• Verify error handling for malformed messages
• Test WebSocket subprotocol

Motivation and Context

Thorough testing of the WebSocketClientTransport is essential to ensure robust client-server communication in our application. These tests verify both normal operation and error handling capabilities.

Type of changes

• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Test improvement (expanded test coverage for existing functionality)

How Has This Been Tested?

• Created dedicated test suite for WebSocketClientTransport
• All tests pass successfully
• Tested connection handling, message processing, error conditions, and protocol negotiation
• Used mock WebSocket implementation to simulate browser behavior in Node.js

Checklist:

• My code follows the code style of this project
• I have added tests to cover my changes
• All new and existing tests passed
• My changes generate no new warnings