Revert using random port by default

Revert change introduced in https://github.com/qbittorrent/qBittorrent/pull/11637 and also revert the associated follow-up https://github.com/qbittorrent/qBittorrent/pull/12000.

Reason: https://github.com/arvidn/libtorrent/pull/4335

src/app/upgrade.cpp

@@ -93,8 +93,7 @@ void handleChangedDefaults(const DefaultPreferencesMode mode)
     };
 
     const QVector<DefaultValue> changedDefaults {
-        {QLatin1String {"BitTorrent/Session/QueueingSystemEnabled"}, true, false},
-        {QLatin1String {"BitTorrent/Session/UseRandomPort"}, false, true}
+        {QLatin1String {"BitTorrent/Session/QueueingSystemEnabled"}, true, false}
     };
 
     SettingsStorage *settingsStorage {SettingsStorage::instance()};

src/base/bittorrent/session.cpp

@@ -436,7 +436,7 @@ Session::Session(QObject *parent)
     , m_isBandwidthSchedulerEnabled(BITTORRENT_SESSION_KEY("BandwidthSchedulerEnabled"), false)
     , m_saveResumeDataInterval(BITTORRENT_SESSION_KEY("SaveResumeDataInterval"), 60)
     , m_port(BITTORRENT_SESSION_KEY("Port"), -1)
-    , m_useRandomPort(BITTORRENT_SESSION_KEY("UseRandomPort"), true)
+    , m_useRandomPort(BITTORRENT_SESSION_KEY("UseRandomPort"), false)
     , m_networkInterface(BITTORRENT_SESSION_KEY("Interface"))
     , m_networkInterfaceName(BITTORRENT_SESSION_KEY("InterfaceName"))
     , m_networkInterfaceAddress(BITTORRENT_SESSION_KEY("InterfaceAddress"))