qt: Fix status bar icons ignoring update activity setting.

Disabling status bar icons activity was left unimplemented on qt.
Prevent refreshing the icons and clear their activity status on setting
change.

src/qt/qt_machinestatus.cpp

@@ -366,6 +366,10 @@ hdd_count(int bus)
 void
 MachineStatus::refreshIcons()
 {
+    /* Check if icons should show activity. */
+    if (!update_icons)
+        return;
+
     for (size_t i = 0; i < FDD_NUM; ++i) {
         d->fdd[i].setActive(machine_status.fdd[i].active);
         d->fdd[i].setEmpty(machine_status.fdd[i].empty);
@@ -399,6 +403,23 @@ MachineStatus::refreshIcons()
     }
 }
 
+void
+MachineStatus::clearActivity()
+{
+    for (auto &fdd : d->fdd)
+        fdd.setActive(false);
+    for (auto &cdrom : d->cdrom)
+        cdrom.setActive(false);
+    for (auto &zip : d->zip)
+        zip.setActive(false);
+    for (auto &mo : d->mo)
+        mo.setActive(false);
+    for (auto &hdd : d->hdds)
+        hdd.setActive(false);
+    for (auto &net : d->net)
+        net.setActive(false);
+}
+
 void
 MachineStatus::refresh(QStatusBar *sbar)
 {

src/qt/qt_machinestatus.hpp

@@ -70,6 +70,7 @@ public:
     static void iterateNIC(const std::function<void(int i)> &cb);
 
     QString getMessage();
+    void    clearActivity();
 public slots:
     void refresh(QStatusBar *sbar);
     void message(const QString &msg);

src/qt/qt_mainwindow.cpp

@@ -2231,6 +2231,9 @@ MainWindow::on_actionUpdate_status_bar_icons_triggered()
 {
     update_icons ^= 1;
     ui->actionUpdate_status_bar_icons->setChecked(update_icons);
+
+    /* Prevent icons staying when disabled during activity. */
+    status->clearActivity();
 }
 
 void