Update launch.json with python backend path

[pamelafox]

Purpose

This PR adds the python property to the Quart launch.json configuration, so that the debugger selects Python interpreter in the correct virtual environment.

Does this introduce a breaking change?

[ ] Yes
[X] No

Pull Request Type

What kind of change does this Pull Request introduce?

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Documentation content changes
[X] Other... Please describe:

How to Test

• Without running pip install at the root, try to use the Quart debug configuration. It should work!