[codespaces] Python virtual environment setup

[danieljurek]

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When launching Python codespaces alerts come up before build... What's the earliest time we could/should run the vscode azd restore command? Python projects should also communicate with the Python extension, if possible, and indicate the appropriate interpreter (this could get interesting with multiple python projects)

Example error message in first run:

Example error message in first debugging run:

To fix:

1. Run the "Restore API" task to get a python virtual environment on the instance
2. Ctrl+Shift+P > Python: Select Interpreter ... select the one created in the restore step