Shape data loss when creating control point on shape that extends beyond last stop of a pattern.

[evansiroky]

Observed behavior (please include a screenshot if possible)

Given a pattern that has a shape that extends beyond the last stop... when trying to insert a control point between the last two stops of the pattern and when moving the control point... then the shape data is changed from the 2nd to the last stop all the way to the end of the shape.

Expected behavior

Given (same as obsserved) when (same as obsserved) then the shape data should be changed only between the 2nd to last stop and the last stop while the shape data after the last stop should remain the same (or alternately, a new shape is created for the pattern that does not extend beyond the last stop, but still the shape is anchored between the stops, not between the last shape point.)

Steps to reproduce the problem

Load the Capitol Corridor GTFS into the editor and try to edit the pattern geometry by creating a new control point and moving that control point between the last 2 stops on route "Capitol Corridor" on pattern "10 stops from Oakland Coliseum to Sacramento (1 trips)"

Any special notes on configuration used

The editor module needs to be enabled.

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

datatools-ui: d06b8136fbd7478d0214e7abcf12f343023205b4 datatools-server: https://github.com/conveyal/datatools-server/commit/566e4da3242f1c79b0e509e358bc639752d0d254