Ungauged node: incorrect definition of donor with Reservoir and bug with Diversion nodes

Bug reported by Florian (https://forgemia.inra.fr/in-wop/seinebasin2/-/issues/40).

In case of a reservoir downstream, this one is selected as donor, which is a wrong selection. The next hydrological node downstream should be selected.

In case of a Diversion node downstream, this is one is correctly selected (A Diversion node contains a hydrological model), but apparently the calibration goes wrong.