bug#38730: 27.0.50; tutorial start does not take into account the customization notice

[Eli Zaretskii <eliz@gnu.org>]

> From: Jean-Christophe Helary <jean.christophe.helary@traduction-libre.org>
> Date: Tue, 24 Dec 2019 18:37:57 +0900
> 
> When starting the Tutorial in an emacs session that has modified
> keybindings, an information notice is displayed in red/bold characters at the top of the screen.
> 
> That notice pushes the first step of the tutorial to below the visible space of the frame. The user thus cannot see the first step and has to manually scroll down to see it, which defeats the purpose of that first step where the user learns to use C-v to move one screenful down...

I'm not sure what use case is described here.  If keybindings have
been modified, we probably aren't talking about a complete newcomer to
Emacs, so at least simple cursor motion should already be a skill
he/she already acquired, right?  He/she might already know to scroll
with PgDn or the mouse wheel, right?

OTOH, in a customized session, we can reasonably expect to see a
window that is larger than the default shown by "emacs -Q", and maybe
then the beginning of the tutorial will still be visible?

And if none of the above helps, then what kind of solution would you
propose for such a situation?