Desktop: Fixes #9613: Fix rich text editor deletes HTML links to notes

[personalizedrefrigerator]

Summary

This only fixes #9613 in HTML notes. It is still an issue in markdown notes.

Partially fixes #9613.

Notes

• (Minor) remaining issue: <a href=":/2cdf0b7c25124dda92421d7a839c21be">Test</a> has its href changed to joplin://2cdf0b7c25124dda92421d7a839c21be.
  • The joplin://2cdf0b7c25124dda92421d7a839c21be link is still clickable (so seems to be a minor issue).
• Adding convert_urls: false to the TinyMCE configuration object also seems to fix the issue in markdown notes. However, this change could lead to regressions (e.g. with pasting from the internet) and is thus best left for a separate pull request (not to be backported into release-2.13).

Related: #9647.

Testing

1. Create a new HTML note
2. Open the rich text editor
3. Drag and drop a note into the rich text editor to create a link
4. Ctrl-Click on the link
5. Go back
6. Edit the note
7. Ctrl-Click on the link again
8. Go back
9. Inspect the HTML for the note (Markup editor)
10. Click on the link in the preview pane

This has been successfully tested on Ubuntu 23.10.