Document Webull 2FA deployment option

[AlexCatarino]

Summary

lean-cli #659 added the optional --webull-use-2fa option for live deployments, and the cloud Deploy Live wizard now shows an Enable 2FA check box for Webull. This PR updates the docs to match:

• Account Types: some clients can disable 2FA for the Webull application (availability depends on region); those who keep it enabled declare it when deploying.
• Deploy Live Algorithms (Cloud Platform): adds the Enable 2FA check box step.
• Deploy Cloud/Local Algorithms (Lean CLI): adds the 2FA prompt to the example sessions.
• QuantConnect-Platform-2.0.0.yaml: adds the optional webull-use-2fa boolean to WebullBrokerageSettings.
• Create Live Algorithm API reference: regenerated with API-Reference-Code-Generator.py (separate commit).

The Lean CLI API Reference (05 Lean CLI/99 API Reference) already includes --webull-use-2fa from the automated regeneration, so no changes there.

Test Plan

• python -c "import yaml; yaml.safe_load(open('QuantConnect-Platform-2.0.0.yaml', encoding='utf-8'))" passes.
• Re-ran API-Reference-Code-Generator.py and Lean-CLI-API-Reference-Code-Generator.py; only the intended Webull section changed.
• Verified the new anchor /docs/v2/cloud-platform/live-trading/brokerages/webull#16-Deploy-Live-Algorithms matches the existing page numbering.