Surface vbat_duration_for_warning/critical CLI settings in the configurator UI

[DavidAnson]

Is your feature request related to a problem? Please describe

Someone asked for this feature in the JB Discord and most people were not aware it existed. Making these CLI values settable in the UI would help more people find them.

https://betaflight.com/docs/development/Battery#configuration

Describe the solution you'd like

Add two new input fields

Describe alternatives you've considered

N/A

Other information

No response

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs within a week.

[DavidAnson]

Activity to reset stale timer.