Hello!

Describe the bug
I've been using this extension in conjunction with VSCode's Liveshare feature. Everything was working fine until a few days ago, since which time this extension does simply not work. I don't see any code highlighting, everything's just grey. I can't do any code navigation, nor can I even use a simple cmd + /. Quaintly enough, VSCode live share works perfectly for shared YAML or JSON files.
On the host's computer, all highlighting works perfectly, but on another editor's computer, the Dart extension simply doesn't work. It displays an error; "This plugin doesn't support virtual workspaces." I commented on the issue regarding support for virtual workspaces, and a maintainer requested me to file a separate issue.

To Reproduce
Steps to reproduce the behavior:

1. Install the LiveShare extension pack
2. Start a session
3. Join the session from another computer
4. Open any shared .dart file.
5. See error

Expected behavior
Code highlighting, code navigation, general working of an extension.

Screenshots

Versions (please complete the following information):

• VS Code version: v1.56
• Dart extension version: v3.22.0
• Dart/Flutter SDK version: Channel stable, 2.0.4, >=2.7.0 <3.0.0 in pubspec.yaml. Not converted to null-safe yet because packages don't support it.

Thank you so much in advance.