Dashbaord import doesn't work - not possible to type OVERWRITE

### Bug description

It seems when important dashboard it doesn't give option to type OVERWRITE and so it doesn't pass int in overwrite=true context. This flow works for charts, not for dashboards.

This happens on Superset 6.1

### Screenshots/recordings

### Superset version

master / latest-dev

### Python version

3.9

### Node version

16

### Browser

Chrome

### Additional context

_No response_

### Checklist

- [ ] I have searched Superset docs and Slack and didn't find a solution to my problem.
- [ ] I have searched the GitHub issue tracker and didn't find a similar bug report.
- [ ] I have checked Superset's logs for errors and if I found a relevant Python stacktrace, I included it here as text in the "additional context" section.