merge tests for public datasets in a single file

[SiQube]

merged public datasets utilities into single file.

resolves #381

I stumbled upon this issue when working on #379. I think this is user friendlier to add more datasets (just add one line to public_dataset parametrize in in the file instead of copying file etc.)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (968e418) to head (9272da0).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #785   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           63        63           
  Lines         2946      2946           
  Branches       782       782           
=========================================
  Hits          2946      2946           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.