Migrate back legacy code to duo chat unified webview - Pinned Context

Checklist

• I'm using the latest version of the extension (see the latest version in the right column of this page)
  • Extension version: Put your extension version here
• I'm using the latest VS Code version (find the latest version here)
  • VS Code version: Put your VS Code version here
• I'm using a supported version of GitLab (see README for the supported version)
  • GitLab version: Put your GitLab version here, or say "happens on gitlab.com"

Summary

Steps to reproduce

What is the current bug behavior?

What is the expected correct behavior?

Relevant logs and/or screenshots

Possible fixes