mainwindow: Don't clear the "updating" flag in updateCard() too early.

The prepareMenu() call can change the active profile selection, which
in turn will cause a "set card profile" command to be sent to the
server if the "updating" flag is not set, so the "updating" flag needs
to be set when calling prepareMenu() from updateCard().

This caused a problem with disconnecting bluetooth headsets: as part
of the disconnection procedure, module-bluetooth-device sets the card
profile to "off". At that point module-card-restore doesn't do
anything, because the change is marked as "don't save". But the
profile change event is then sent to pavucontrol, which updates its
view, and pavucontrol sends the new profile ("off") back to
pulseaudio, and this time the profile change iss marked as "please
save", so module-card-restore restores the "off" profile when the
device is connected again, even though the user never requested the
"off" profile to be chosen.

src/mainwindow.cc

@@ -346,12 +346,12 @@ void MainWindow::updateCard(const pa_card_info &info) {
         }
     }
 
-    w->updating = false;
-
     w->prepareMenu();
 
     if (is_new)
         updateDeviceVisibility();
+
+    w->updating = false;
 }
 
 bool MainWindow::updateSink(const pa_sink_info &info) {