fix: converting bullet list item with the ordered number contents(v2)

[js87zz]

Please check if the PR fulfills these requirements

• It's the right issue type on the title
• When resolving a specific issue, it's referenced in the PR's title (e.g. fix #xxx[,#xxx], where "xxx" is the issue number)
• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes/features)
• Docs have been added/updated (for bug fixes/features)
• It does not introduce a breaking change or has a description of the breaking change

Description

sample data

const editor = newEditor({
  // ...
  initialValue: '* 1. ordered num\n    *  child1\n    * child2'
});

as-is

to-be

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Thank you for your contribution to TOAST UI product. 🎉 😘 ✨

[lja1018]

리뷰완료합니다.

[jwlee1108]

리뷰 완료합니다.

[adhrinae]

리뷰 완료합니다.