core/excerpt-block - Missing </div> in render_block_core_post_excerpt() when showMoreOnNewLine

[bobbingwide]

Describe the bug
I'm using the post-excerpt block in a query-loop in an experimental FSE theme.
I noticed that the background styling had extended to subsequent sections of the output.
The generated HTML was missing the </div> tag.

A clear and concise description of what the bug is.

To reproduce
Steps to reproduce the behavior:

1. In a Full Site Editing theme create a home.html template file containing the post-excerpt block

<!-- wp:query-loop -->
<!-- wp:post-excerpt -->
<!-- wp:post-excerpt /-->

2. View the blog posts.
3. Inspect the output.

The generated HTML for an excerpt will be something like this

<div class=&quot;wp-block-post-excerpt&quot;>
<p class="wp-block-post-excerpt__excerpt">
Twenty Twenty-One is a blank canvas for your ideas and it makes the block editor your best brush. With new block patterns, which allow you to create a beautiful layout in a matter of seconds, this theme’s soft colors and eye-catching — yet timeless — design will let your work shine. Take it for a [&hellip;]
</p>
<p class="wp-block-post-excerpt__more-text"></p>

Expected behavior
There should be </div> for each excerpt.

Screenshots
Before:

After applying the fix I took the opportunity to get rid of the greeny background

Editor version (please complete the following information):

• WordPress version: [e.g: 5.3.2] 5.5.1
• Does the website has Gutenberg plugin installed, or is it using the block editor that comes by default? [e.g: "gutenberg plugin", "default"] 9.2.2 or latest extract from the repo.
• If the Gutenberg plugin is installed, which version is it? [e.g., 7.6]

Desktop (please complete the following information):

• OS: [e.g. iOS] Windows
• Browser [e.g. chrome, safari] Chrome
• Version [e.g. 22] 86.0.4240.111 (Official Build) (64-bit)

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context
Suggested fix:
Append </div> to line 39 of post-excerpt.php

if ( ! isset( $attributes['showMoreOnNewLine'] ) || $attributes['showMoreOnNewLine'] ) {
		$output .= '</p>' . '<p class="wp-block-post-excerpt__more-text">' . $more_text . '</p></div>';