Force validation differently for met location list changes

Startup, load gen5 save file.
Immediately load a pk3; met location is converted to Poketransfer
When data is prepared, the validation fails and the selectedvalue is reset to 0
Future selectedvalue sets will work

Just force validation when we change the list, so that future value sets work.
Weird winforms quirk
https://stackoverflow.com/questions/14624129/setting-combobox-droppeddown-false-resets-selected-item

PKHeX.WinForms/Controls/PKM Editor/PKMEditor.cs

@@ -1278,7 +1278,7 @@ private void ReloadMetLocations(GameVersion version, int format)
             }
             else
             {
-                CB_GameOrigin.Focus(); // hacky validation forcing
+                ValidateChildren(); // hacky validation forcing
             }
         }