Don't change preview notebook selection when editing

This causes focus change (on GTK at least), plus the user might
not want the notebook to change in the first place.

Fixes https://gitlab.com/kicad/code/kicad/-/issues/5477

pcbnew/dialogs/dialog_pad_properties.cpp

@@ -323,7 +323,6 @@ void DIALOG_PAD_PROPERTIES::updateRoundRectCornerValues()
         m_tcChamferRatio1->ChangeValue( ratio );
     }
 
-    m_previewNotebook->ChangeSelection( 0 );
     redraw();
 }