Strange / buggy behaviour of launch configurations

[Wim-De-Clercq]

There's a couple of issues:

1. The "select a debug configuration" popup appears twice when creating a launch configuration
2. Creating another configuration doesn't create a launch configuration in the launch.json but somehow does add an entry called Python Debugger: Python File
3. Clicking the edit launch configuration button crashes. And after this, the extra launch configuration from 2. has disappeared again.

launch.configurations.mp4

[eleanorjboyd]

@connor4312 any ideas here? Not sure if the UI elements have anything to do with Core or just the extension.