The previous approach (`hideIntoWidgets`) flagged optional widgets as
hidden and zeroed their compute size, but left them in node.widgets.
Canvas-drawn LiteGraph widgets that remain attached to the node still
have a hit-test region — they intercepted clicks meant for the new
custom dropdown / + button, changing the cursor and opening the
hidden widget's editor instead of the dropdown.
Rename to `removeIntoWidgets` and actually splice these widgets out of
node.widgets so there is no hit region left. Add an idempotency guard
on setupIntoFlakeDataSelect so the second call (from onConfigure) is a
no-op rather than re-adding the DOM widget twice.
Closes#214