Bug: ctrl+Z doesn't always undo

[mvitale1989]

Steps to reproduce the behavior

1. Go to focalboard
2. Open a card
3. Type a comment
4. Delete a single character with backspace
5. Press ctrl+Z

Expected behavior

I expect ctrl+Z to restore the character i deleted. Instead, nothing happens.

Edition and Platform

• Edition: the one on the community server, as of today
• Version: v7.4.2
• Browser and OS: both on Firefox 105.0.3, and on the Mattermost desktop client. OS is Ubuntu 22.04

Additional context

This is Sev 3 (minor, non-critical functionality), but it can become a bit frustrating when typing long comments in particular. E.g. something gets deleted by mistake, and it cannot be restored in any way. I am currently typing my comments on a text editor first, then copypasting them into the card, in order to avoid running into this issue again.

A few cases in which ctrl+Z didn't work:

• Type a comment -> delete single character -> press ctrl+Z (it should restore the deleted character, but doesn't)
• Type a comment -> press ctrl+backspace to delete the last word -> press ctrl+Z (it should restore the deleted word, but doesn't)
• Type a comment -> press ctrl+Z (should delete the last word or letter that was typed, but doesn't)

Interestingly, there's also a case in which ctrl+Z worked well:

• Type a comment -> select it all with ctrl+A -> press backspace to delete it -> press ctrl+Z (it successfully restores the full deleted comment, as expected)