[LyX/master] Check for NULL pointer earlier

[Jürgen Spitzmüller]

Am Sonntag, dem 20.10.2024 um 06:05 +0000 schrieb Juergen Spitzmueller:
> commit 5ec247a957f446ed0bb26fe958d11aec95c3325c
> Author: Juergen Spitzmueller <spitz at lyx.org>
> Date:   Sun Oct 20 08:05:06 2024 +0200
> 
>     Check for NULL pointer earlier
>     
>     Reported by Coverity

Should also go to stable.

-- 
Jürgen