Archwiki has similar solution for another HP laptop but with a different kernel fixup option
https://wiki.archlinux.org/index.php/Laptop/HP#Mute_led
create a file with a text editor
(any text editor will do, but nano is usually present on any Manjaro DE)
sudo nano /etc/modprobe.d/mute.conf
add this text to the file
options snd-hda-intel model=hp-mute-led-gpio
save file - Ctrl + O and exit nano - Ctrl + X
then reboot system to load new modprobe option