Append missing </div> to post-excerpt block (#26581)

[bobbingwide]

Description

In the core/post-excerpt block there's logic that tests if the showMoreOnNewLine attribute is set.
When it was missing or true then the generated HTML was missing a trailing </div>.

This fix adds the missing </div>.

How has this been tested?

• Tested in a local environment with WordPress 5.6-beta3
• Tested where the only plugin is Gutenberg
• Tested with the Twenty Twenty-One Blocks theme
• Added a <wp:post-excerpt> to a template and demonstrated - using View Source - that the end div tag was no longer missing.

Screenshots

With this simple test setup there was no visible effect to the displayed output.

Types of changes

• Fixes core/excerpt-block - Missing </div> in render_block_core_post_excerpt() when showMoreOnNewLine #26581
• This PR replaces my previous PR Append missing </div> to post-excerpt block (#26581) #26785

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.
• I've updated all React Native files affected by any refactorings/renamings in this PR.

I can't honestly tick some of the above in the checklist since I don't have a wp-env environment.
This means I can't run the PHPUnit tests, nor other npm run commands that expect it.

[talldan]

Thanks for catching the issue and putting together the fix!

[aristath]

Good catch!
LGTM 👍

[talldan]

In terms of the tests, the static analysis issue was fixed in #26811, and the failing end to end test is one that exists in master, related to an issue in a framework we use for accessibility testing (dequelabs/axe-core-npm#98).

So I'll go ahead and merge this.