Do not run unsubmitted form warning for tabs in PDF document mode
To reproduce:
- Paste a large enough amount of text into a form to trigger the unsubmitted form warning, but don't close the tab
- Load a PDF document in the tab
- Close the tab
Expected behavior: no unsubmitted form warning for tabs in document mode Actual behavior: it runs the unsubmitted form warning because the code doesn't know about document mode