bug#43065: Fix or remove broken flyspell-issue-welcome-flag option

[Eli Zaretskii]

> From: Stefan Kangas <stefan@marxist.se>
> Date: Thu, 27 Aug 2020 02:27:13 -0700
> Cc: 43065@debbugs.gnu.org
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Btw, can we make this only display the welcome message if
> > flyspell-mode is invoked interactively?  Your patch makes this
> > unconditional, which I don't think was the original intent.
> 
> (I received your email less than a minute after pushing.)
> 
> Your observation is correct, I think.
> 
> Is this one of those places where we are forced to use
> (called-interactively-p 'interactive)?

Yes, I think so.