fix(identicon): don't set identicon as an avatar

Do not save user's identicon to a file like a normal avatar. This allows
'Use identicons' setting to affect user's own identicon.

src/persistence/profile.cpp

@@ -477,9 +477,6 @@ void Profile::setAvatar(QByteArray pic, const ToxPk& owner)
             // with IDENTICON_ROWS=5 this gives a 160x160 image file
             const QImage identicon = Identicon(owner.getKey()).toImage(32);
             pixmap = QPixmap::fromImage(identicon);
-            QBuffer buf(&avatarData);
-            buf.open(QIODevice::WriteOnly);
-            identicon.save(&buf, "png");
 
         } else {
             pixmap.load(":/img/contact_dark.svg");