HDF5Utils.sort_h5items change in 5.9.5+

[stuart-cls]

We have some files that usually contain ['/dark_current', '/mono_0', '/pvs'] as the top-level entries.

In HDF5Utils.sort_h5items, the list_to_sort gets set the following by _extract_sort_key_from_name:

[('/dark_current', ('dark_current', <HDF5 group "/dark_current" (1 members)>)), 
((0,), ('mono_0', <HDF5 group "/mono_0" (31 members)>)), 
('/pvs', ('pvs', <HDF5 group "/pvs" (1 members)>))]

Then we get a TypeError when making the sorted_list on line 124 because you can't compare a string ('dark_currrent') and a tuple ((0,))

Introduced in #1110

Thanks!