Support Bicep extension in vscode.dev and github.dev

The Bicep extension depends on dotnet installed locally, and doesn't work in the VSCode web editor.

We should be able to get this working with Blazor's WASM support.

Related investigations:
https://github.com/OmniSharp/csharp-language-server-protocol/issues/456
https://github.com/dotnet/aspnetcore/issues/37732

Web Extension authoring guide:
https://code.visualstudio.com/api/extension-guides/web-extensions

Start by reading the Web Extension authoring guide and inspect how the Bicep extension depends on locally installed dotnet. Review the linked language-server and ASP.NET Core investigations to understand the Blazor WASM path. Done means the Bicep extension works in both vscode.dev and github.dev without a local dotnet installation.

Written by the indexing model from the issue text.