Fix accounts avatar issue when it becomes completely white due to non…

…-changing account id member with changing account index in the list.

Signed-off-by: allexzander <blackslayer4@gmail.com>

src/gui/tray/usermodel.cpp

@@ -912,10 +912,15 @@ bool UserModel::isUserConnected(const int id)
 
 QImage UserModel::avatarById(const int id)
 {
-    if (id < 0 || id >= _users.size())
+    const auto foundUserByIdIter = std::find_if(std::cbegin(_users), std::cend(_users), [&id](const OCC::User* user) {
+        return user->account()->id() == QString::number(id);
+    });
+
+    if (foundUserByIdIter == std::cend(_users)) {
         return {};
+    }
 
-    return _users[id]->avatar();
+    return (*foundUserByIdIter)->avatar();
 }
 
 QString UserModel::currentUserServer()