Conditional `if array is None` behavior

**Bug**
Some pattern involving array switch on conditional and function broke after 0.14. I haven't tracked down exactly when, but 0.14.2 is broken.
This has been first identified in the larger Pace model - the NASA fork.

While trying to reproduce the actual error, I encounter a slightly different one. So let start here, but be aware they might be more.

**Reproducer**
```python
import dace
import numpy as np

def a_function(array, scalar: np.float32, optional_array=None):
if optional_array:
tmp_array = optional_array
else:
tmp_array = array

tmp_array[:] = scalar

@dace.program
def a_program(array, scalar: np.float32, optional_array):
a_function(array, scalar)
a_function(array, scalar, optional_array)

arr = np.ones((4), dtype=np.float32)
opt_arr = np.ones((4), dtype=np.float32)
s = np.float32(3.0)

a_program(arr, s, opt_arr)

assert (arr == s).all()
assert (opt_arr == s).all()
```

**Expected behavior**
0.14: assert are fine, code works as intent (both arrays are init)
0.14.2: callback is triggered for no reason then conditional fails to parse

**Notes**
There's no identified workaround for this apart code duplication which would be significant and a risk to maintenance on our side. Therefore this regression blocks us from updating DaCe.