Ensure line distances for speed calculations match Data Dashboard

[devinmatte]

Paired with transitmatters/t-performance-dash#1028

We're getting slightly different numbers between the speed numbers generated here and the trip specific speed numbers on the Data Dashboard.

The worst offender is the Mattapan line

Dashboard Data	Ingestor Data

We should use the same distance info as https://github.com/transitmatters/t-performance-dash/blob/main/common/constants/station_distances.json