Closes #31951 The fix is copied and translated from copilot chat actual implementation code: https://github.com/microsoft/vscode-copilot-chat/blob/ad7cbcae9a964e8efb869bf1426999e56ea63cf0/src/platform/openai/node/fetch.ts#L493C1-L495C3 Release Notes: - Fix copilot failing due to missing `Copilot-Vision-Request` from request.