Validate the value in the first and last property of wxPropertyGrid

wxPGProperty value edited in the first or last property of wxPropertyGrid
should be validated while attempting to navigate to the previous/next
property.

Closes #19315.

src/propgrid/propgrid.cpp

@@ -5803,6 +5803,11 @@ void wxPropertyGrid::HandleKeyEvent( wxKeyEvent &event, bool fromChild )
                 if ( reopenLabelEditorCol >= 0 )
                     DoBeginLabelEdit(reopenLabelEditorCol);
             }
+            else if ( action == wxPG_ACTION_EDIT )
+            {
+                // For first and last item just validate the value
+                CommitChangesFromEditor();
+            }
             wasHandled = true;
         }
     }