pidgin/pidgin

Re-subclass PidginPresenceIcon onto GtkBox as GtkImage is final in Gtk4

Testing Done:
Verfied that the infopane showed the icon properly with no new warnings.

Reviewed at https://reviews.imfreedom.org/r/1413/
syntax: glob
.*.swp
.DS_Store
.flatpak-builder
*.pyc
*~
\#*\#
syntax: regexp
^build(.+)?\/
win32-install-dir(\.release)?
po\/pidgin\.pot$
^subprojects\/.+\/