front: using config stored in db for stdcm v2

[sim51]

Fix #8239

To test it, you need to insert a row in the table stdcm_search_environment

[codecov-commenter]

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Codecov Report

Attention: Patch coverage is 2.43902% with 200 lines in your changes missing coverage. Please review.

Project coverage is 37.49%. Comparing base (39e7b9d) to head (b1d22a4).

Files	Patch %	Lines
...ont/src/applications/stdcmV2/hooks/useStdcmEnv.tsx	0.00%	49 Missing and 1 partial ⚠️
...ont/src/applications/stdcmV2/views/StdcmViewV2.tsx	0.00%	35 Missing ⚠️
.../src/applications/stdcm/utils/formatStdcmConfV2.ts	0.00%	27 Missing ⚠️
...rc/applications/stdcmV2/components/StdcmOrigin.tsx	0.00%	26 Missing and 1 partial ⚠️
...tions/stdcmV2/components/StdcmEmptyConfigError.tsx	0.00%	20 Missing and 1 partial ⚠️
front/src/reducers/osrdconf/stdcmConf/index.ts	5.26%	18 Missing ⚠️
editoast/src/views/v2/timetable/stdcm.rs	0.00%	15 Missing ⚠️
...rc/applications/stdcmV2/components/StdcmHeader.tsx	0.00%	6 Missing ⚠️
.../src/reducers/osrdconf/osrdConfCommon/selectors.ts	0.00%	1 Missing ⚠️

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Additional details and impacted files

@@             Coverage Diff              @@
##                dev    #8336      +/-   ##
============================================
+ Coverage     37.07%   37.49%   +0.41%     
  Complexity     2165     2165              
============================================
  Files          1265     1253      -12     
  Lines        117058   115653    -1405     
  Branches       3137     3139       +2     
============================================
- Hits          43404    43366      -38     
+ Misses        71814    70445    -1369     
- Partials       1840     1842       +2     

Flag	Coverage Δ
core	74.94% <ø> (ø)
editoast	66.38% <0.00%> (-0.04%)	⬇️
front	15.77% <1.59%> (-0.03%)	⬇️
gateway	?
osrdyne	2.71% <ø> (ø)
railjson_generator	87.49% <ø> (ø)
tests	73.00% <100.00%> (+0.02%)	⬆️

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[flomonster]

Thanks for this PR.

[clarani]

LGTM & tested ✅

[bloussou]

test part is ✅

[sim51]

I squashed my commits

[flomonster]

LGTM!