Admin promotion categories add/edit

[chaimann]

Summary

Addresses #6102

Continuation of the work on new Admin UI, to convert add/edit pages into modal forms, this will add modal forms for both old and new promotion categories, as well as changing index page to render turbo-links to items

Checklist

• I agree that my PR will be published under the same license as Solidus.
• I have written a thorough PR description.
• I have kept my commits small and atomic.
• I have used clear, explanatory commit messages.
• ✅ I have added automated tests to cover my changes.
• 📸 I have attached screenshots to demo visual changes.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.45%. Comparing base (ec1c421) to head (c87a012).
Report is 25 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #6101      +/-   ##
==========================================
+ Coverage   86.62%   92.45%   +5.83%     
==========================================
  Files         511      391     -120     
  Lines       11809     8035    -3774     
==========================================
- Hits        10229     7429    -2800     
+ Misses       1580      606     -974     

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[chaimann]

quite sure this was a typo as the code below is situated in config/initializers/spree.rb, commented out after generator run

[chaimann]

this was needed for page title to display correctly

[chaimann]

for page title to display correctly

[kennyadsl]

Not sure I fully understand why we need to change the legacy promotion code. We already had a promotion categories CRUD in there, so what's the need to change it? Maybe I'm missing something, and tagging @mamhoff who probably has the best understanding of that part.

[mamhoff]

Promotion categories are easy enough to do for both extensions. The more common stuff we have in the new admin the better I think.

The one thing I would not touch is the promotion form for legacy promotion. That is just too much work.

[chaimann]

@kennyadsl my understanding is that since legacy promotions is the default dependency which users use until they migrate to solidus_promotions, we need to make sure its UI is uniform with other admin pages, that are/will be updated with modal forms.
As @mamhoff mentioned, both categories systems UI are easy to add changes to since UI is the same, while promotions UI is not part of this ticket and won't be changed

[kennyadsl]

👌

[tvdeyen]

Awesome! Thanks 👍🏻