[ESSreduce] The polarization package imports from ESSsans

[jl-wynen]

src/ess/reduce/polarization/zoom.py imports a couple of things from modules in ESSsans:

from ess.isissans.io import LoadedFileContents
from ess.sans.types import (
    Filename,
    Incident,
    MonitorType,
    NeXusComponent,
    NeXusMonitorName,
    RunType,
    SampleRun,
    Transmission,
    TransmissionRun,
)

This is backwards because polarization is now in ESSreduce. Also, the tests are not failing, so it seems like we are not testing this module.