Excerpts don't include content from list-item blocks.

[dougwollison]

Currently, excerpt_remove_blocks() allows the list block, but not the newer (since 6.0) list-item block. This results in all content contained in lists from being excluded from the excerpt.

[dougwollison]

Adds core/list-item to $allowed_inner_blocks

[abcd95]

I've successfully reproduced the issue and tested the patch. Here's my verification:

Steps to Reproduce Used:

1. Created a test post with this structure:
   • Paragraph block with text "Before the list"
   • List block with items:
     • First item in list
     • Second item in list
     • Third item with some detailed text
   • Paragraph block with text "After the list"

2. Before Patch:
   • Checked excerpt in post listing
   • Only paragraph content appeared ("Before the list. After the list.")
   • All list content was missing from excerpt

3. After Applying Patch:
   • Added 'core/list-item' to $allowed_inner_blocks
   • Checked excerpt again
   • Full content appears correctly including list items

This confirms that:

1. The issue is resolved by including core/list-item block
2. Excerpts now maintain proper content flow
3. No regression in other block content handling

Before applying the patch -
After applying the patch -

✅ The patch successfully fixes the excerpt generation for list content while maintaining expected excerpt behavior for other blocks. 👍

This PR resolves an issue where content within list-item blocks was excluded from post excerpts. The function excerpt_remove_blocks() now allows core/list-item as part of $allowed_inner_blocks, ensuring that list content is correctly included in generated excerpts.

Trac ticket: https://core.trac.wordpress.org/ticket/62417