Interstitial order field doesn't always update after a run is removed from the schedule

[uraniumanchor]

Describe the bug

If a run is removed from the schedule, all runs after it have their order decremented by one. Anchored interstitials should also immediately be decremented, but it some cases they do not.

To Reproduce

1. Have 3 runs in order, the third with an anchored interstitial.
2. Remove run 2 from the schedule.
3. Anchored interstitial order field disagrees with its anchor.

Expected behavior

The former third run updates its order to 2, as well as all the interstitials.

[uraniumanchor]

On further review this -might- be that somebody was able to delete a run that still had an order, not the schedule editor drag operation.