Some extension icons do not display correctly in WSL and Dev Container

Does this issue occur when all extensions are disabled?: Yes

- VS Code Version:
```
Version: 1.139.0-insider (user setup)
Commit: 046944034292b5479b4e9a50ad1a508033ffb64f
Date: 2026-09-17T03:41:14Z
Electron: 43.6.0
ElectronBuildId: 15274685
Chromium: 150.0.7871.250
Node.js: 24.20.0
V8: 15.0.245.31-electron.0
@github/copilot: 1.0.84-5
@github/copilot-sdk: 1.0.13
OS: Windows_NT x64 10.0.26200
```
- OS Version: Windows 11

Steps to Reproduce:

1. Open a WSL window, wait for the remote window to be fully set up
1. Open Chat, from the view menu select `Show chat debug view`
1. Verify whether the chat debug view has an icon or not

The chat debug view icon is not displayed (the same problem also apply to some extensions).

In DevTools, I see some icon-related requests showing `(failed)net::ERR_FAILED`, for example:
```
vscode-remote-resource://127.0.0.1:50364/insider-046944034292b5479b4e9a50ad1a508033ffb64f/vscode-remote-resource?path=.vscode-server-insiders%2Fbin%2F046944034292b5479b4e9a50ad1a508033ffb64f%2Fextensions%2Fcopilot%2Fassets%2Fdebug-icon.svg&tkn= net::ERR_FAILED
```

Previous similar issue - https://github.com/microsoft/vscode/issues/318954