fix: handle 246 status code for stream responses

[VisargD]

Title: fix: handle 246 status code for stream responses

🔄 What Changed

• Added status code 246 to the list of success status codes for streaming responses
• Updated conditional checks throughout the code to use the new isSuccessStatusCode variable
• Enhanced the afterRequestHookHandler to return a 246 status code for streaming responses when hooks fail
• Modified handleJSONToStreamResponse to preserve status code and status text in streaming responses

🔍 Impact of the Change

• Improves handling of streaming responses when hooks fail without deny enabled
• Provides better signaling to clients about partial success with hook failures
• Maintains consistency in status code propagation throughout the response pipeline

📁 Total Files Changed

• 2 files modified: src/handlers/responseHandlers.ts and src/handlers/streamHandler.ts
• Total changes: 39 lines (25 additions, 14 deletions)

🧪 Test Added

N/A - No tests were added in this PR

🔒 Security Vulnerabilities

N/A - No security vulnerabilities were introduced or addressed

Related Issues:

• Fixes Handle before_request_hooks (deny: false) failure for stream responses #1013