Clicking Routes tab in FeedVersion Summary causes error if no routes present in GTFS

[landonreed]

Observed behavior (please include a screenshot if possible)

1. Upload GTFS file that has no routes.txt file (e.g., this one).
2. Click Routes tab
3. Error encountered (see screenshot)

Expected behavior

No error. GraphQL request should either not be fired off if route count is zero. Or gtfs-lib should handle missing table gracefully.

Steps to reproduce the problem

See above.

Any special notes on configuration used

N/A

Version of datatools-ui and datatools-server if applicable (exact commit hash or branch name)

latest dev