Reified circuit first element of list is restricted

[Wout4]

I was looking more into the MTZ decomposition of circuit, and noticed that our current implementation still has a bug:
The defining part restricts the first variable of the circuit to be in the range of the length of the list. Putting this in a negative context does not yield all possible solutions if the first variable can take values outside of this domain.

[Wout4]

it's actually for all variables, not only the first one. Proposed a fix that makes the decomposition (slightly slower)