Bug 2175811

Description of problem:
I had Acccessibility Help opened and I enabled High Contrast in Settings -> Accessibility. The first it replaced the document with a sad face, that it can't be rendered. After I reopened Help and tried again, the whole Help crashed after enabling High Contrast.

Version-Release number of selected component:
yelp-2:42.2-2.fc38

Additional info:
reporter:       libreport-2.17.8
type:           CCpp
reason:         yelp killed by SIGSEGV
journald_cursor: s=f14ac85b1ea64de087f79c5fe57e0ea5;i=12abce;b=cdbd1bf69de04d41a66d144057234d85;m=1dc5d35ac;t=5f63cc4bd324d;x=d9e1efc005c5e5df
executable:     /usr/bin/yelp
cmdline:        /usr/bin/yelp help:gnome-help/a11y
cgroup:         0::/user.slice/user-1000.slice/user/app.slice/dbus-:1.2-org.gnome.Settings.SearchProvider
rootdir:        /
uid:            1000
kernel:         6.2.2-300.fc38.x86_64
package:        yelp-2:42.2-2.fc38
runlevel:       N 5
dso_list:       /usr/bin/yelp yelp-2:42.2-2.fc38.x86_64 (Fedora Project) 1678091587
backtrace_rating: 4
crash_function: document_callback
comment:        I had Acccessibility Help opened and I enabled High Contrast in Settings -> Accessibility. The first it replaced the document with a sad face, that it can't be rendered. After I reopened Help and tried again, the whole Help crashed after enabling High Contrast.

Truncated backtrace:
Thread no. 1 (8 frames)
 #0 document_callback at libyelp/yelp-view.c:783
 #1 request_idle_contents at libyelp/yelp-document.c:1442
 #5 g_main_context_iterate.isra.0 at ../glib/gmain.c:4276
 #6 g_main_context_iteration at ../glib/gmain.c:4343
 #7 g_application_run at ../gio/gapplication.c:2573
 #8 __libc_start_call_main at ../sysdeps/nptl/libc_start_call_main.h:58
 #9 __libc_start_main_impl at ../csu/libc-start.c:360
 #10 _start