Polyglot Notebook: [NetTestingE2E][Regression]Error "The editor could not be opened due to an unexpected error..." throw up while reopening the VScode.

[v-huanli1]

REGRESSION:
Not repro on VSCodeSetup-1.106.3+ dotnet-interactive-vscode-1.0.6603011.vsix+dotnet-sdk-9.0.308.

Describe the bug:
Error "The editor could not be opened due to an unexpected error..." throw up while closing and reopening the VSCode.

Steps:

1. Install sdk https://dotnet.microsoft.com/en-us/download/dotnet/thank-you/sdk-10.0.101-windows-x64-installer
2. Install VScode and dotnet-interactive-vscode-1.0.6609011.vsix
3. Download the notebook from https://github.com/dotnet/interactive/blob/main/NotebookTestScript.dib and open it via vscode
4. Close and reopen the vscode

Build info:
Detailed Repro Build info: VSCodeSetup-x64-1.106.3 +dotnet-interactive-vscode-1.0.6609011.vsix
VSCode Link: https://code.visualstudio.com/insiders/#
dotnet-interactive-vscode-1.0.6609011.vsix
https://dev.azure.com/dnceng/internal/_build/results?buildId=2857756&view=results
Sdk info: dotnet-sdk-9.0.308-win-x64.exe

Version: 1.106.3 (system setup)
Commit: bf9252a2fb45be6893dd8870c0bf37e2e1766d61
Date: 2025-11-25T22:28:18.024Z
Electron: 37.7.0
ElectronBuildId: 12781156
Chromium: 138.0.7204.251
Node.js: 22.20.0
V8: 13.8.258.32-electron.0
OS: Windows_NT x64 10.0.26200

Actual Results:
Error "The editor could not be opened due to an unexpected error..." throw up when reopening the VScode again.

Expected Results:
The notebook should be opened in Visual Studio Code without any issue.

Please complete the following:

Which version of .NET Interactive are you using? (In a notebook, run the #!about magic command. ):

• OS
  • [ √] Windows 11
  • Windows 10
  • macOS
  • Linux (Please specify distro)
  • iOS
  • Android
• Browser
  • Chrome
  • Edge
  • Firefox
  • Safari
• Frontend
  • Jupyter Notebook
  • Jupyter Lab
  • nteract
  • [ √] Visual Studio Code
  • Visual Studio Code Insiders
  • Visual Studio
  • Other (please specify)