Remove User Preferences Handling from BatchXPDialog

[IllianiCBT]

Removed the entire setUserPreferences method, along with associated imports.

Storing preferences caused a lot of fragility with this system. It was very easy for a user to accidentally brick their Mass Training dialog by moving between different campaigns if those campaigns had different skill set ups. For example, if Campaign A had Piloting/Mek cap out at 8, while B had it cap out at 10. Moving from B to A could prevent the Mass Training dialog being used entirely if the user had their target level set to 9 or 10.

User preferences, in this instance, just stored the last known configuration for the Mass Training dialog. Given how few options there are - and the fact that it doesn't appear to have stored configurations on a per-skill basis - I opted to remove preferences entirely.

Fixes #5542

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 10.02%. Comparing base (2af7e1a) to head (449266e).
Report is 18 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5550      +/-   ##
============================================
- Coverage     10.03%   10.02%   -0.02%     
+ Complexity     6053     6036      -17     
============================================
  Files          1073     1073              
  Lines        141198   141173      -25     
  Branches      20565    20566       +1     
============================================
- Hits          14175    14151      -24     
+ Misses       125662   125660       -2     
- Partials       1361     1362       +1     

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