ui: remove unused MapPanel function (#28874)

forgot about this

selfdrive/ui/qt/maps/map_panel.cc

@@ -28,7 +28,3 @@ MapPanel::MapPanel(const QMapboxGLSettings &mapboxSettings, QWidget *parent) : Q
   });
   content_stack->addWidget(settings);
 }
-
-bool MapPanel::isShowingMap() const {
-  return content_stack->currentIndex() == 0;
-}

selfdrive/ui/qt/maps/map_panel.h

@@ -10,8 +10,6 @@ class MapPanel : public QFrame {
 public:
   explicit MapPanel(const QMapboxGLSettings &settings, QWidget *parent = nullptr);
 
-  bool isShowingMap() const;
-
 private:
   void showEvent(QShowEvent *event) { emit mapWindowShown(); };