MainApplication: Load UserAgentManager settings before NetworkManager

NetworkManager depends on UserAgentManager being loaded.

Fixes user agent settings not being applied on startup.

src/lib/app/mainapplication.cpp

@@ -962,8 +962,8 @@ void MainApplication::loadSettings()
     }
 
     qzSettings->loadSettings();
-    networkManager()->loadSettings();
     userAgentManager()->loadSettings();
+    networkManager()->loadSettings();
 }
 
 void MainApplication::loadTheme(const QString &name)