gnome: add different avatar for conferences

Create avatar with two symbolic people to distinguish a conference.

Issue: #79076
Change-Id: Ie6b4b33af4d8fae2a188c23cb7cb5877bb64f199
diff --git a/src/native/pixbufmanipulator.h b/src/native/pixbufmanipulator.h
index 77ec780..8b7e43b 100644
--- a/src/native/pixbufmanipulator.h
+++ b/src/native/pixbufmanipulator.h
@@ -63,6 +63,7 @@
 private:
     std::shared_ptr<GdkPixbuf> scaleAndFrame(const GdkPixbuf *photo, const QSize& size);
     std::shared_ptr<GdkPixbuf> fallbackAvatar_;
+    std::shared_ptr<GdkPixbuf> conferenceAvatar_;
 };
 
 } // namespace Interfaces