core: return all etcs curves in response

[Erashin]

We'll be returning all the curves to the front end in the near future. This is just a preview draft where all of the intermediate curves are computed. See #9702

[codecov-commenter]

⚠️ Please install the to ensure uploads and comments are reliably processed by Codecov.

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.78%. Comparing base (74a2bcb) to head (a1ce4e4).
Report is 3 commits behind head on dev.

❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@            Coverage Diff             @@
##              dev   #10473      +/-   ##
==========================================
- Coverage   81.78%   81.78%   -0.01%     
==========================================
  Files        1073     1073              
  Lines      106580   106580              
  Branches      731      731              
==========================================
- Hits        87166    87164       -2     
- Misses      19375    19377       +2     
  Partials       39       39              

Flag	Coverage Δ
editoast	74.21% <ø> (-0.01%)	⬇️
front	89.34% <ø> (ø)
gateway	2.18% <ø> (ø)
osrdyne	3.28% <ø> (ø)
railjson_generator	87.50% <ø> (ø)
tests	87.05% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

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