Remove space-wasting app backup copy

Details

I've noticed that Karabiner creates an app dupe on install in Karabiner-Elements.app.tar.gz, apparently for "recovery" purposes

# Create a backup to allow recovery if the user manually deletes Karabiner-Elements without using the uninstaller
tar -C /Applications -cf '/Library/Application Support/org.pqrs/Karabiner-Elements/Karabiner-Elements.app.tar.gz' Karabiner-Elements.app

But the recovery for such a strange use case is trivial and also most natural

• the user will check the trash bin
• the user will just download the app again and install it again

There is no reason everyone should waste space carrying a whole full app copy to guard against this