As already discussed on another forum!!!!!!
It is definitely NOT Fraxinus excelsior...common name ASH TREE.
Sorry but I do not believe that it is a seedling of Fraxinus excelsior...common name Ash tree.
Ash trees have compound leaves.
I attach pics to show you a single ash leaf with multiple leaflets.
It has a terminal leaflet at the tip. (While your shrub ends with a pair of leaves)
The leaflets are different sizes getting smaller as they get near the trunk.(Your shrub does not do this)
1st pic below shows a close up of your leaves.