image-customization: Remove reminder for wifi-fallback

Wifi-fallback is a great idea, if you are tryping to change anything on
your network, that may isolate mesh-only nodes.

At the moment we are not planning on doing any such changes.
Also: our `gluon-ffbs-autoupdater-wifi-fallback` package is not state of
the art anymore. Today we would probably want to base our package on the
community-package version.
(But for parker this would still need some careful testing anyway.)

image-customization.lua

--- Notes to ourselfs (from the past):
--- activate for wifi fallback later in production
---       gluon-ffbs-autoupdater-wifi-fallback
-
 features({
 	'web-advanced',
 	'web-osm',