Update dev container to make tutorial notebooks work again

[FH-Inway]

When reviewing the existing tutorial notebooks, I noticed they no longer work. This is due to two reasons:

1. The Visual Studio Code Polyglot Notebooks extension by now depends on .NET 9.0. The GitHub codespaces .devcontainer was updated.
2. The Visual Studio Code Polyglot Notebooks extension currently has an error (see Polyglot Notebook VS Code: Notebooks outputting .NET objects instead of PowerShell dotnet/interactive#4024). This produces unusable output for some commands. The GitHub codespaces .devcontainer was updated to pin the extension to an earlier version that does not have this error.