editoast: add consist params validation

[Wadjetz]

fix #9543

Adding backend validation for the consists values to prevent calculation errors.

[codecov-commenter]

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Codecov Report

Attention: Patch coverage is 98.68421% with 1 line in your changes missing coverage. Please review.

Project coverage is 81.85%. Comparing base (da06215) to head (bfe451f).
Report is 21 commits behind head on dev.

Files with missing lines	Patch %	Lines
editoast/src/views/timetable/stdcm.rs	94.44%	1 Missing ⚠️

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Additional details and impacted files

@@            Coverage Diff             @@
##              dev   #10332      +/-   ##
==========================================
+ Coverage   81.83%   81.85%   +0.01%     
==========================================
  Files        1081     1081              
  Lines      106879   106946      +67     
  Branches      721      721              
==========================================
+ Hits        87466    87538      +72     
+ Misses      19372    19367       -5     
  Partials       41       41              

Flag	Coverage Δ
editoast	74.39% <98.68%> (+0.06%)	⬆️
front	89.38% <ø> (ø)
gateway	2.18% <ø> (ø)
osrdyne	3.28% <ø> (ø)
railjson_generator	87.50% <ø> (ø)
tests	88.14% <ø> (ø)

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[bougue-pe]

After discussing in the office, the main goal of the issue is to protect from unclear crash.
The front part already does the main job, so we should just protect the backend from unclear crashes, without narrowing use when it's technically OK (at a reasonable cost).

👍 Thanks for getting rid of a new part of the 'validator' use 🎉

[bougue-pe]

LGTM.
Feel free to resolve those 2 comments if applied.

[SharglutDev]

Lgtm for front (not tested)

[bougue-pe]

LGTM, just please squash before merge 🙏

[leovalais]

It would have been great to have numerical values instead of a generic message string :/

Because of that, 1) the full error message is split in several places and 2) in tests you have to assert_eq on strings instead of numerical values which are more stable.