build Docker jobs fail, but devel jobs are fine

[KrisThielemans]

We see in the build jobs

ERROR: test_SIRF (unittest.loader._FailedTest)
----------------------------------------------------------------------
ImportError: Failed to import test module: test_SIRF
Traceback (most recent call last):
  File "/opt/conda/lib/python3.10/unittest/loader.py", line 436, in _find_test_path
    module = self._get_module_from_name(name)
  File "/opt/conda/lib/python3.10/unittest/loader.py", line 377, in _get_module_from_name
    __import__(name)
  File "/home/jovyan/cil_sirf_test/test_SIRF.py", line 29, in <module>
    from cil.optimisation.utilities import AdaptiveSensitivity
ImportError: cannot import name 'AdaptiveSensitivity' from 'cil.optimisation.utilities' (/opt/conda/lib/python3.10/site-packages/cil/optimisation/utilities/__init__.py)

This is likely due to #877. The test is currently run with test_SIRF.py from CIL master.

@casperdcl what do you think? I'll create a PR anyway