Refactor draw buffer handling

main/display/lvgl_handler.h

@@ -31,10 +31,4 @@ private:
   lv_display_t* lvgl_display_ = nullptr;
   lv_indev_t* lvgl_touch_indev_ = nullptr;
   lv_draw_buf_t* lvgl_draw_buf_ = nullptr;
-  uint8_t* framebuffer_ = nullptr;
-  bool framebuffer_in_psram_ = false;
-  RefreshArea refresh_area_ = { 0, 0, 0, 0 };
-
-
-  SemaphoreHandle_t lvgl_mutex_ = nullptr;
 };