fix: update last modified on icon change

[Xazin]

Closes: #3409

Feature Preview

https://github.com/AppFlowy-IO/AppFlowy/assets/42929161/32bc5066-8df9-4ef8-87ff-f50dcfe92c46

PR Checklist

• [x] My code adheres to AppFlowy's Conventions
• [x] I've listed at least one issue that this PR fixes in the description above.
• [ ] I've added a test(s) to validate changes in this PR, or this PR only contains semantic changes.
• [x] All existing tests are passing.

[LucasXu0]

Please don't merge it before releasing version 0.5.1.