core: fix cache_status_endpoint

[younesschrifi]

fix cache_status endpoint. It returned an error if the infra had not been downloaded instead of returning an empty dictionary

[codecov]

Codecov Report

Merging #4249 (c2f3216) into dev (f1bc357) will decrease coverage by 0.03%.
The diff coverage is 93.87%.

@@             Coverage Diff              @@
##                dev    #4249      +/-   ##
============================================
- Coverage     21.14%   21.11%   -0.03%     
  Complexity     2118     2118              
============================================
  Files           827      827              
  Lines         81589    81556      -33     
  Branches       2097     2098       +1     
============================================
- Hits          17251    17221      -30     
+ Misses        63146    63142       -4     
- Partials       1192     1193       +1     

Flag	Coverage Δ
core	80.38% <50.00%> (-0.01%)	⬇️

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

Impacted Files	Coverage Δ
editoast/src/core/pathfinding.rs	100.00% <ø> (ø)
...st/src/models/rolling_stock/light_rolling_stock.rs	97.14% <ø> (ø)
editoast/src/models/rolling_stock/mod.rs	92.50% <ø> (-0.36%)	⬇️
editoast/src/schema/rolling_stock/mod.rs	87.50% <ø> (ø)
editoast/src/tables.rs	0.00% <ø> (ø)
editoast/src/views/pathfinding/mod.rs	91.25% <ø> (-0.10%)	⬇️
editoast/src/views/rolling_stocks.rs	34.44% <ø> (-25.30%)	⬇️
...ava/fr/sncf/osrd/api/InfraCacheStatusEndpoint.java	77.14% <50.00%> (-2.27%)	⬇️
editoast/src/views/infra/mod.rs	94.19% <94.28%> (+0.16%)	⬆️
front/src/common/api/osrdEditoastApi.ts	91.57% <100.00%> (+0.07%)	⬆️

... and 1 file with indirect coverage changes