front: api: minor fixes on rolling stock selector

[clarani]

close #3047

• load the rollingStock image before the render
• remove transform in RollingStock image css
• rolling stocks cards should not be transparent if no rs is selected

[codecov]

Codecov Report

Merging #3052 (95e6214) into dev (8a588f5) will increase coverage by 0.03%.
The diff coverage is 0.00%.

@@             Coverage Diff              @@
##                dev    #3052      +/-   ##
============================================
+ Coverage     38.66%   38.69%   +0.03%     
  Complexity     1708     1708              
============================================
  Files           605      605              
  Lines         18770    18765       -5     
  Branches       2516     2516              
============================================
+ Hits           7258     7262       +4     
+ Misses        11103    11095       -8     
+ Partials        409      408       -1     

Flag	Coverage Δ
front	4.79% <0.00%> (+0.04%)	⬆️

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

Impacted Files	Coverage Δ
...t/src/applications/customget/views/TrainDetails.js	0.00% <ø> (ø)
front/src/applications/opendata/OpenDataImport.js	0.00% <0.00%> (ø)
...rc/applications/opendata/components/TrainDetail.js	0.00% <ø> (ø)
...nageTrainSchedule/Itinerary/ModalPathJSONDetail.js	0.00% <0.00%> (ø)
...omponents/ManageTrainSchedule/TimetableSelector.js	0.00% <0.00%> (ø)
...tionResults/Allowances/StandardAllowanceDefault.js	0.00% <ø> (ø)
...ents/SimulationResults/Allowances/withOSRDData.tsx	0.00% <ø> (ø)
...onents/TimetableSelector/TimetableSelectorModal.js	0.00% <0.00%> (ø)
front/src/applications/stdcm/getStdcmTimetable.js	0.00% <ø> (ø)
.../src/applications/stdcm/views/StdcmRequestModal.js	0.00% <ø> (ø)
... and 16 more

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[flomonster]

Good for api