Describe the bug
Selecting the green run button in the debugger view open a launch.json file with the version and configuration tags. If you add in the configuration (e.g. JLink) and save the file. The configuration is not saved. It does not appear in the drop list of configurations and if you hit the green run button again it opens a new blank except for {} launch.json file and a dialog warning asking if you want to overwrite the changes to .theia/launch.json.

To Reproduce
Steps to reproduce the behavior:

1. Go to 'Debug View'
2. Click on 'Run'
3. Complete the configuration and save it.
4. See that it's not available in the debugger configuration drop list.
5. Click on 'Run' again
6. See that a new nearly blank launch.json file is created and an overwrite warning dialog is issued.

Expected behavior
The debugging configuration should be saved. It should be visible in the configuration drop list. Pressing the green run button once the configuration is saved should launch the debugging session.

Screenshots
Configuration set and saved

After pressing the run button once saved.

Desktop (please complete the following information):

• OS: MacOS 11.2.3 (Big Sur)
• Version: Arduino IDE 2.0.0-beta.4

Additional context
Add any other context about the problem here.