Partial multi selection: undo should restore selection in correct place

[ellatrix]

Description

Follow up to #38892.
Selection is currently not restored correctly after undoing a merge.

Step-by-step reproduction instructions

Select multiple blocks partially. Merge with Backspace. Undo the operation. The partial multi selection should be restored.

Screenshots, screen recording, code snippet

No response

Environment info

No response

Please confirm that you have searched existing issues in the repo.

Yes

Please confirm that you have tested with all plugins deactivated except Gutenberg.

Yes

[github-actions]

Hi,
This issue has gone 180 days without any activity. This means it is time for a check-in to make sure it is still relevant. If you are still experiencing this issue with the latest versions, you can help the project by responding to confirm the problem and by providing any updated reproduction steps.
Thanks for helping out.

[Thelmachido]

Hi @ellatrix there hasn't been much movement on this one or the PR you linked lately.

Are there any plans to continue moving this forward?

[ellatrix]

Yes, this is an issue that must be solved.