Issue #3558719 by jessebaker: Linking and unlinking a field does not correctly reset the form view to it's initial state

Closes #3558719

This MR ensures that the 'sourceTypeSettings' are sent back when patching component instance after unlinking. This is a client side fix.

I do wonder if the API should be relying on what data the client is sending to this PATCH endpoint. Does the server know the component that is being patched and can it therefore access the correct/original 'sourceTypeSettings' rather than having to rely on them being sent in the request.