Don't update map if it really didn't change

rust/src/game_manager.rs

@@ -431,6 +431,9 @@ impl Game {
     }
 
     pub fn change_map_selection(&mut self, map_idx: u8, emit: bool) {
+        if self.selected_map_idx == map_idx {
+            return;
+        }
         self.selected_map_idx = map_idx;
         if let Some(map) = self.maps.get(map_idx as usize) {
             self.selected_map = Some(map);