Fix Met tab startup binding

`ListControl._dataManager` is null until some event fires, which never happens until the Visible state is normally triggered by flipping to that tab.

The met tab Version/Location can skip Visibility changes on startup, resulting in never being initialized by the GUI framework, thus ignoring any calls to change SelectedValue. Really weird, but setting the BindingContext here forces it to create a `_dataManager` when setting a new `DataSource`.

Closes #4384

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

@@ -104,7 +104,10 @@ public sealed partial class PKMEditor : UserControl, IMainEditor
             CB_AlphaMastered,
         ];
         foreach (var cb in cbs.Concat(Relearn))
+        {
+            cb.BindingContext = BindingContext;
             cb.InitializeBinding();
+        }
 
         IsInitialized = true;
     }