Undo button doesn't work after clearing the survey

[RomanTsukanov]

Steps to reproduce:

1. Open the Survey Creator
2. Make sure that the survey is empty. Otherwise, click the Clear Survey button.
3. Add a question.
4. Click the Clear Survey button.
5. Click the Undo button.

Result: Nothing happens Expected result: The survey is the same as before Clear Survey is clicked.

[andrewtelnov]

@RomanTsukanov We have to clear undo/redo state as well on clear.