Do not refresh PCB canvas when clearing every selected item.

It only needs to be done once after all of the items are updated.

Fixes https://gitlab.com/kicad/code/kicad/-/issues/21332

(cherry picked from commit 63ec5af8a1)

pcbnew/pcb_base_frame.cpp

@@ -273,16 +273,21 @@ void PCB_BASE_FRAME::FocusOnItems( std::vector<BOARD_ITEM*> aItems, PCB_LAYER_ID
 {
     static std::vector<KIID> lastBrightenedItemIDs;
 
+    bool itemsUnbrightened = false;
+
     for( KIID lastBrightenedItemID : lastBrightenedItemIDs )
     {
         if( BOARD_ITEM* lastItem = GetBoard()->ResolveItem( lastBrightenedItemID, true ) )
         {
             lastItem->ClearBrightened();
             GetCanvas()->GetView()->Update( lastItem );
-            GetCanvas()->Refresh();
+            itemsUnbrightened = true;
         }
     }
 
+    if( itemsUnbrightened )
+        GetCanvas()->Refresh();
+
     lastBrightenedItemIDs.clear();
 
     if( aItems.empty() )