Pattern Inserter: Multiple undo histories are created

[t-hamano]

Description

When I insert a pattern, multiple undo histories are created, so I cannot delete a pattern unless I press the Undo button several times after inserting it. The amount of history created depends on the pattern inserted.

I looked back through the commit history and it looks like this issue first appeared in #61915.

Step-by-step reproduction instructions

After inserting a pattern, click the Undo button.

Screenshots, screen recording, code snippet

Before #61915

before.mp4

After #61915

after.mp4

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

[Mamaduka]

@t-hamano, the source PR for the bug seems incorrect. It's also the same PR that should fix it.

[t-hamano]

@Mamaduka Thanks for pointing that out! I've corrected the PR number.