fix(NcRichText): include all label items

[DorraJaouad]

☑️ Resolves

Breaking change:

event 'interact:todo' now returns a string (id of the affected checkbox) instead of an object.

• Fix Mentions are broken in "todo lists" with github markdown patch nextcloud/spreed#12009

• Checkbox includes different elements in its label
• Added explicit indentation for nested lists
• Interactivity: used the DOM to calculate the position of the element and then use it in the string

🖼️ Screenshots

🏚️ Before	🏡 After

Interactivity:

Recording.2024-04-08.102641.mp4

🏁 Checklist

• ⛑️ Tests are included or are not applicable
• 📘 Component documentation has been extended, updated or is not applicable
• 3️⃣ Backport to next requested with a Vue 3 upgrade

[ShGKme]

Works much better than before, but sub-lists are still a little bit broken

Before	After

## Test

List:
- List1
  - Sub item 1
- List 2
  - Sub item 2

Tasks:
- [ ] Task 1
- [ ] @"Test Offline" **open** [web-page](https://nextcloud.com) 
  - [ ] One
  - [ ] Two

[Antreesy]

Left a couple of comments. Good workaround with handling the correct line!

P.S. I'd also suggest to enable extended markdown in Usage with NcRichContenteditable example, for checking mention parsing

[susnux]

/backport to next