Fix value mapping for bikesAllowed in GTFS GraphQL API

[leonardehrenfried]

Summary

If you request the bikesAllowed resolver of the GTFS API it would incorrectly return the value NOT_POSSIBLE when it should be NOT_ALLOWED, according to the schema. This would lead to an error for the resolver instead of the value.

This PR fixes this problem.

Unit tests

Added.

[codecov]

Codecov Report

Patch coverage: 71.42% and project coverage change: +0.01% 🎉

Comparison is base (a27baf3) 66.49% compared to head (0abf7f3) 66.51%.

Additional details and impacted files

@@              Coverage Diff              @@
##             dev-2.x    #5368      +/-   ##
=============================================
+ Coverage      66.49%   66.51%   +0.01%     
- Complexity     15234    15236       +2     
=============================================
  Files           1785     1786       +1     
  Lines          69269    69266       -3     
  Branches        7291     7291              
=============================================
+ Hits           46063    46069       +6     
+ Misses         20737    20728       -9     
  Partials        2469     2469              

Files Changed	Coverage Δ
.../gtfsgraphqlapi/generated/GraphQLDataFetchers.java	0.00% <ø> (ø)
...ext/gtfsgraphqlapi/mapping/BikesAllowedMapper.java	60.00% <60.00%> (ø)
...ner/ext/gtfsgraphqlapi/datafetchers/RouteImpl.java	20.61% <100.00%> (+0.81%)	⬆️
...nner/ext/gtfsgraphqlapi/datafetchers/TripImpl.java	19.18% <100.00%> (+0.43%)	⬆️

... and 3 files with indirect coverage changes

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