[Bug] Bullet and numbered lists display spaces and placeholder text if no content exists, but include child nodes

### Bug Description

Bullet and numbered lists are not rendered correctly if a list element doesn't contain any content but contains child nodes like a paragraph.

If no bullet or numbered list content exists, an empty space and a placeholder text will be displayed:

### How to Reproduce

Following minimal HTML produces a document which will be rendered as explained above:

```dart
htmlToDocument('

1. test

')
```

Extended example (used for the screenshot):

```dart
htmlToDocument('

1. ol Line 1

   ol Line 2

2. ol Line 3

   ol Line 4

• ul Line 1

  ul Line 2

• ul Line 3

  ul Line 4

')
```

This can be reproduced by replacing the HTML string at https://github.com/AppFlowy-IO/appflowy-editor/blob/796d1249fe5a7f936cb9060208561c45db484098/example/lib/home_page.dart#L143.

### Expected Behavior

No empty space and no placeholder text should be displayed in this case.
The nested content should move up to be aligned with the bullet symbol:


Maybe only in `editable: false` mode?

### Operating System

iOS (simulator)

### AppFlowy Editor Version(s)

2.4.0

### Screenshots

_No response_

### Additional Context

_No response_