Application error when general calibrations files are none

[ivenzor]

    imageData = apply_cals(imageData, generalDark, generalBias, generalFlat, i)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/dist-packages/exotic/exotic.py", line 916, in apply_cals
    if gen_flat.size != 0:
       ^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'size'

This was introduced in one on my changes, merged in 4.3.0