It was specially made for that item, you won't find an exact replacement (unless maybe the manufacturer would have
one they'll sell you).
I don't know your skill level (or exactly what that switching device is supposed to do, because it does have an
on/off switch outside of it).
I'd try to determine what the broken switching device is supposed to do, and see if you can come up with a way
to duplicate its function.
Is it the 'lamp socket' itself that we're looking at maybe?