TaskEditor removes time values when updating

[chuckn0rris]

Forum post

If tasks have time values for start/end date, the task editor removes time values when updating tasks regardless of modification of the dates.
And even worse, tasks have mismatching of dates and duration when it happens.

To reproduce, try to change the name of task in Task Editor and click save.

It can be reproduced at https://bryntum.com/examples/gantt/advanced/.

duration_mismatch.mp4

[chuckn0rris]

other steps to reproduce may be found here #4120