Don't set batch offset when creating image sequences

[jbeilstenedmands]

This should now be unnecessary following #634 and related changes.

Removes an unintended use of the batch offset property

Fixes dials/dials#1347

Will not be merged without thorough testing and discussion.

[codecov]

Codecov Report

Merging #662 (cb9ba90) into main (cd03663) will decrease coverage by 0.01%.
Report is 1 commits behind head on main.
The diff coverage is 80.00%.

❗ Current head cb9ba90 differs from pull request most recent head 06657c4. Consider uploading reports for the commit 06657c4 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #662      +/-   ##
==========================================
- Coverage   41.97%   41.96%   -0.01%     
==========================================
  Files         182      182              
  Lines       15885    15886       +1     
  Branches     3047     3047              
==========================================
  Hits         6667     6667              
- Misses       8608     8609       +1     
  Partials      610      610              

[ndevenish]

Holding off for more testing

[dwpaley]

Running XFEL tests here:
https://github.com/cctbx/cctbx_project/tree/test_dxtbx_662

[dwpaley]

Currently all good with respect to XFEL CI tests :)

[jbeilstenedmands]

I have run the dials and xia2 tests, however some of the xia2.ssx tests are failing with this change, due to the use of the batch offset in dials.ssx_integrate when slicing an imageset.
I need to investigate further whether I can work around this, I thinkn in theory it should be possible.

[jbeilstenedmands]

After further testing, I believe we do still need this functionality for recording when the first image in an imageset is not 0/1, even if it is not used for slicing the imageset, so I am closing this. Any later uses of the batch offset, e.g. in dials.export, should take this into account.