fix current index, depends on value of setting

fix default value of the combobox for the collapse lines, incorrectly
always shows first item of the box, instead of current value

src/widgets/settingspages/AppearancePage.cpp

@@ -85,6 +85,14 @@ AppearancePage::AppearancePage()
             auto *combo = new QComboBox(this);
             combo->addItems({"Never", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12",
                              "13", "14", "15"});
+            const auto currentIndex = []() -> int {
+                auto val = getApp()->settings->collpseMessagesMinLines.getValue();
+                if (val > 0) {
+                    --val;
+                }
+                return val;
+            }();
+            combo->setCurrentIndex(currentIndex);
 
             QObject::connect(combo, &QComboBox::currentTextChanged, [](const QString &str) {
                 getApp()->settings->collpseMessagesMinLines = str.toInt();