Fix connector

Context

import aidge_core as ac

x = ac.Connector()
x = ac.FC(3,3)(x) # error!
y1 = ac.FC(3,3)(x)
y2 = ac.FC(3,3)(x)

model = ac.generate_graph([y1,y2])

The Node object raises an assertion because inputs 1 and 2 are not empty.

It should only check Data input instead of each input

Modified files

Node.cpp