Disable hardware-acceleration-policy on Gtk 4.x (it is done for Gtk 3.x
already) as  first frame is never drawn when using accelerated
compositing (GPU path). The DOM loads, signals fire, but the view stays
blank.
Different value compared to Gtk 3 is due to the fact that the setting no
longer has always/ondemand/never but just always/never on Gtk 4.