Travel simulator may try to simulate invalid data

In some datasets, the travel simulator may throw the following error:

```
travel-simulator.component.ts:98 ERROR Error: coord is required
    at getPointAlongPathByDistance (linear-referencing.ts:40:26)
    at map.selectors.ts:221:48
    at Array.forEach (<anonymous>)
    at getSimulatedVehicleLocationsOnRouteWithHeadings (map.selectors.ts:183:10)
    at map.selectors.ts:243:5
```