Set CHROME_DESKTOP to the appropriate value

[rany2]

This value should always be <app_id>.desktop. Not setting this is known to cause weird issues with wrong icons being displayed by the DE (chromium-browser icon shown instead of the actual browser icon under certain circumstances) and causes the icon to not show up for a couple of seconds under GNOME Wayland when Chromium is not configured to use Wayland with the --ozone-platform=wayland flag.