Provide user choice when clicking coincident nodes

[Nate-Wessel]

The "intersection" of Park Lawn and the Gardiner has nodes doubled up - one on the lower way, one on the highway. It's impossible to route consistently without being able to choose which gets selected.

[Nate-Wessel]

Query that leads to the problem:
https://trans-bdit.intra.prod-toronto.ca/tt-request-backend/closest-node/-79.48670983953926/43.626387710970505

The first two points are coincident and we don't have a way of picking one over the other. The third point is further away.