Implement fallback when cannot be used

[sonnyp]

We should fallback when commit cannot be used (no display, over ssh, toolbox, ... for example).

[sonnyp]

@cassidyjames shared a terrible kludge for Toolbx https://floss.social/@cassidy@blaede.family/111207382084737928

[cassidyjames]

@sonnyp apparently installing Flatpak inside of your toolbx container is another way to work around it... so maybe that specific case should be mentioned in the main window?