Prompt users if they already have a .venv

[bamurtaugh]

Testing #19883

I already have a .venv in my project. I was curious what would happen if I went through the Python: Create Environment steps again. I can't tell if anything happened. Should we prompt users if they already have a .venv, allowing them to choose to override it or back out of creating a new .venv and just use the existing one? The Dev Containers extension works similarly: if a user chooses the command to add a dev container config and they already have one, they're asked if they'd like to override or just use the existing one.

[karrtikr]

@karthiknadig Try using

vscode-python/src/client/interpreter/configuration/interpreterSelector/commands/setInterpreter.ts

Line 138 in 870ae8f

const currentInterpreterPathDisplay = this.pathUtils.getDisplayName(

for displaying a user friendly path:

[karrtikr]

We should probably mention in the prompt and the logs that we just selected the existing .venv in the workspace.

[karthiknadig]

Temporary resolution here is that we auto-select the existing environment for now, as the intended users of this command are beginners. This is done.

If we see that people are getting confused by auto-selection, we can provide bit more clarification. For venv there is no way to override other than deleting and re-creating, so we will defer that for now.

For issues mentioned by @karrtikr I have created separate bugs.