Add test to dataset name cache

[evalott100]

Adds a test to dataset name cache.

Also

• pins numpy until p4p incompatible with NumPy 2.0 epics-base/p4p#145 is solved.
• adds some docstrings and comments.
• changes :CAPTURE to a ComboBox widget in the positions capture table.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.31%. Comparing base (efc3822) to head (ad1d097).

❗ Current head ad1d097 differs from pull request most recent head 339ae3a

Please upload reports for the commit 339ae3a to get more accurate results.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #124      +/-   ##
==========================================
+ Coverage   90.94%   91.31%   +0.36%     
==========================================
  Files           8        8              
  Lines        1358     1358              
  Branches      213      213              
==========================================
+ Hits         1235     1240       +5     
+ Misses         83       80       -3     
+ Partials       40       38       -2     

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[AlexanderWells-diamond]

Looks fine but there's a couple of possible improvements that could be made

[AlexanderWells-diamond]

What is a "Dataset" in this context? I don't know enough about this area to know if this is a commonly known topic, or a concept created here for our code.

[evalott100]

It's more of an abstraction - we have the BLOCK_NAME:DATASET record for using an alternative column label in the hdf5 file and the BLOCK_NAME:CAPTURE record for specifying what is captured. class Dataset functions as a more readable way to keep these together in the dict given from ioc.py.