Updated feasible_point to search over scan points

[j-a-foster]

Description

Updates create.py to allow creating new IN.DATs from any point in a scan.

Checklist

I confirm that I have completed the following checks:

• My changes follow the PROCESS style guide
• I have justified any large differences in the regression tests caused by this pull request in the comments.
• I have added new tests where appropriate for the changes I have made.
• If I have had to change any existing unit or integration tests, I have justified this change in the pull request comments.
• If I have made documentation changes, I have checked they render correctly.
• I have added documentation for my change, if appropriate.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 0% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 49.46%. Comparing base (a9358cc) to head (8b48734).

Files with missing lines	Patch %	Lines
process/core/io/in_dat/create.py	0.00%	6 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4552   +/-   ##
=======================================
  Coverage   49.46%   49.46%           
=======================================
  Files         150      150           
  Lines       30069    30068    -1     
=======================================
  Hits        14874    14874           
+ Misses      15195    15194    -1     

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[timothy-nunn]

So I actually think this entire function could do with a re-work.

Even with your fixes there are still a number of issues:

• Negative indexing only works for -1, any other index defaults to scan point 1.
• Scan point 0 silently updates to 1.
• Scan point > number of scans will select the last scan.

I'm also not sure I like the for loop looking for a scan. I think this logic should be simplified so that:

1. We only support scans [1, num_scans] and -1, anything else raises an error.
2. We only check the requested scan (position) for feasibility and error if it is infeasible. In my opinion, if the user wants a scan point they should explicitly index it, we shouldn't be silently searching for a feasible one.

Let me know if you disagree, have any suggestions, or questions.