Generate contract modifiers when adding contracts individually

[Algebro7]

The CamOps contract market had a NPE when contracts were GM-added and the modifiers had not previously been populated on a monthly refresh. This PR populates the modifiers if a contract is added and they haven't been initialized.

Closes #4897

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 10.46%. Comparing base (2b9ba00) to head (e98a6de).
Report is 13 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff            @@
##             master    #4906   +/-   ##
=========================================
  Coverage     10.45%   10.46%           
- Complexity     6006     6011    +5     
=========================================
  Files           952      952           
  Lines        132755   132759    +4     
  Branches      19308    19308           
=========================================
+ Hits          13882    13889    +7     
  Misses       117527   117527           
+ Partials       1346     1343    -3     

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