Fix for sluggish animation or freeze just before GDM

[arthurlutz]

First of all, thanks a lot for these plymouth themes !

In the process of reusing "oldish" hardware, having a boot animation really chances the perception of the user when the machine is taking long to boot.

Unfortunately, the animation speed can be inconsistent when the machine is booting, and even freeze at the very end when switching to GDM.

I guess this is a plymouth or system fix, but maybe some can point me in the right direction ? I looked at https://wiki.archlinux.org/title/Plymouth and didn't find anything on the topic... Thanks in advance for the help.