Replace typings/pythonEnvironments.d.ts with @vscode/vscode-python-environments

[edvilme]

Currently, we are using a hard copy of the exposed api from https://github.com/microsoft/vscode-python-environments

When microsoft/vscode-python-environments#1317 gets merged, we will be able to consume the npm package.

This fix should also be applied to any downstream repos.