Checklists: Can't check/uncheck checklist items in note preview

### Expected

When I preview a markdown note with checklists, I expect to be able to check/uncheck items in the checklist. (This is how the Electron app preview works.)

### Observed

I see the checkboxes, but clicking on them doesn't check or uncheck them.

### Reproduced

1. Create a new note.
2. Go to Info and toggle on Markdown.
3. Add a checklist to the note.
4. Preview the note and try to check/uncheck items in the checklist.


Make|Model|macOS Version|App Version
-|-|-|-
Apple|Macbook Pro|10.15.4|1.10.0 beta

Reproduce the issue by creating a Markdown note with a checklist, opening its preview, and clicking the checkbox. Trace the macOS note preview behavior and compare it with the Electron app preview described in the issue. Done means checklist items can be checked and unchecked from preview as expected.

Written by the indexing model from the issue text.