This was the case for multi input sockets that have a link already.
Since we have multi input sockets, the way we use `socket_is_available`
is not really giving the expected result on these.
When used for input sockets the intention is to find a free socket
(either for noodle **replacement**, then it is always available, or just
the next free available socket).
Now I would think without the intention to replace an existing link, a
multi input socket should still be available.
From the inside of the function, the `replace` argument turns [namewise]
to `allow_used`, which sounds a little different (so one might argue
that if `allow_used` is `False` this should also trigger for already
connected multi input sockets).
In the end, this is an issue with the variable naming though, cant think
of a usecase where the patch change would really go against intentions.
Maniphest Tasks: T93413
Differential Revision: https://developer.blender.org/D13866
a5610da1d5