Fix load error messages not having a stack trace

[RunDevelopment]

While implementing #2507, I forgot the iterator_inputs=IteratorInputInfo(inputs=0) which prevented the node from loading. Those were the errors messages that were logged:

[2024-01-24 16:10:11 +0100] [8492] [WARNING] Failed to load packages.chaiNNer_standard.utility.math.accumulate (C:\Users\micha\Git\chaiNNer\backend\src\packages\chaiNNer_standard\utility\math\accumulate.py):
[2024-01-24 16:10:11 +0100] [8492] [WARNING]

Pretty useless. No message, not even a stack trace. Turns out that logger.warning(e.error) only logs the error message but never the stack trace. So I used exc_info=e.error to get the stack trace.

The full error with stack trace was this btw:

[2024-01-24 16:12:59 +0100] [1608] [WARNING] Failed to load packages.chaiNNer_standard.utility.math.accumulate (C:\Users\micha\Git\chaiNNer\backend\src\packages\chaiNNer_standard\utility\math\accumulate.py):
Traceback (most recent call last):
  File "C:\Users\micha\Git\chaiNNer\backend\src\api\api.py", line 477, in load_nodes
    importlib.import_module(module, package=None)
  File "C:\Python38\lib\importlib\__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
  File "<frozen importlib._bootstrap>", line 991, in _find_and_load
  File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 783, in exec_module
  File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
  File "C:\Users\micha\Git\chaiNNer\backend\src\packages\chaiNNer_standard\utility\math\accumulate.py", line 44, in <module>
    @math_group.register(
  File "C:\Users\micha\Git\chaiNNer\backend\src\api\api.py", line 223, in register
    assert len(iterator_inputs) == 1 and len(iterator_outputs) == 0
AssertionError