BUG: Undo manager start and stop doesnt work as expected

[Harshsne26]

GrapesJS version

• I confirm to use the latest version of GrapesJS

What browser are you using?

Chrome v91

Reproducible demo link

https://codepen.io/dhanadsp1120/pen/ExrRvOB

Describe the bug

How to reproduce the bug?

1. Disable the undo manager by invoking um.stop().
2. Make alterations to the content.
3. Re-enable the undo manager using um.start().

What is the expected behavior?
Upon pressing Ctrl+Z, the system should revert to the state before stopping the undo manager, reflecting only changes made after re-enabling it.

What is the current behavior?
Pressing Ctrl+Z navigates to the preceding step, indicating that all changes are being tracked despite the undo manager being temporarily halted.

Code of Conduct

• I agree to follow this project's Code of Conduct