Not selecting from the version download should cancel the launch

[jw3]

1. Start debugging without a version specified in the launch.json
2. When prompted to select a version, click somewhere outside of the dropdown
3. Observe that the backend continue to launch

The same behavior can be observed if pressing Esc instead of clicking outside the box.

I would expect that if I click somewhere other than in the drop down that the operation would not progress further.