[#2049] Add regression test for eSuite multiple end statustypes

[pi-sigma]

Taiga: #2049

Regression test for cases where eSuite associates multiple statustypen with the same zaaktype. Taiga issue 1971

[pi-sigma]

I took the opportunity to refactor some of the code in the case detail view and add documentation.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (e0528fc) 94.76% compared to head (3094a31) 94.77%.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #989   +/-   ##
========================================
  Coverage    94.76%   94.77%           
========================================
  Files          861      861           
  Lines        30228    30260   +32     
========================================
+ Hits         28646    28678   +32     
  Misses        1582     1582           

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

[stevenbal]

@pi-sigma could you fix the merge conflicts?