feat: Mixed nested list types in Pages

[jordanh]

Description

Before these changes, you couldn't have a check list nested under an ordered list. Now you can!

Demo

Testing scenarios

[Please list all the testing scenarios a reviewer has to check before approving the PR]

• Make a checklist
• Make an ordered list
• Drag the checklist onto an ordered list item. Voila!
• Outdent (shift-tab) the checklist item, now it in ordered list item
• Repeat with indent, it is still an ordered list item

Final checklist

• I checked the code review guidelines
• I have added Metrics Representative as reviewer(s) if my PR invovles metrics/data/analytics related changes
• I have performed a self-review of my code, the same way I'd do it for any other team member
• I have tested all cases I listed in the testing scenarios and I haven't found any issues or regressions
• Whenever I took a non-obvious choice I added a comment explaining why I did it this way
• I added the label Skip Maintainer Review Indicating the PR only requires reviewer review and can be merged right after it's approved if the PR introduces only minor changes, does not contain any architectural changes or does not introduce any new patterns and I think one review is sufficient'
• PR title is human readable and could be used in changelog

[jordanh]

Matt: Is this something that we could submit upstream to tiptap instead?

[jordanh]

You're instinct was correct, this should happen first: ueberdosis/tiptap#4424

Then, this can be refactored and simplified