GTFS transformations - UI state incorrect after deleting an (invalid) transformation step

[binh-dam-ibigroup]

Observed behavior (please include a screenshot if possible)

Deleting a GTFS transformation step that has validation errors results in that same step still being shown at the end of the list.

Expected behavior

The deleted step should not be shown.

Steps to reproduce the problem

1. Create a GTFS transformation
2. Add some steps
3. Add a step with invalid fields.
4. Delete that step
5. Observe that the erroneous step is still shown.

Any special notes on configuration used

NA

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

Recent dev branch.