isWellDefined(ComplexMap) doesn't check if the maps are well-defined

```m2
i1 : S = QQ[x];

i2 : f = map(S^1, S^1/x, 1);

o2 : Matrix

i3 : isWellDefined f

o3 = false

i4 : isWellDefined map(complex target f, complex source f, {f})

o4 = true
```