Steps to reproduce the issue

Publish a mod_articles_category module that shows an article starting with a hyperlinked image, i.e.

<p><a href="alink.html"><img src="animage.png" alt="foo" width="600" height="300"></a></p>
<p>Some text...</p>

Expected result

The image will be removed as well as the hyperlink that has become empty, i.e.

<p class="mod-articles-category-introtext">Some text...</p>

Actual result

Only the image is removed, the hyperlink is still there, hence resulting in an accessibility error (WCAG 2.4.4 success criteria: Link Purpose), i.e.

<p class="mod-articles-category-introtext"><a href="alink.html"></a>Some text...</p>

System information (as much as possible)

Additional comments

in Joomla3 /modules/mod_articles_category/helper.php and
in Joomla4 /modules/mod_articles_category/src/Helper/ArticlesCategoryHelper.php

the function

public static function _cleanIntrotext($introtext)
{
	$introtext = str_replace(array('<p>','</p>'), ' ', $introtext);
	$introtext = strip_tags($introtext, '<a><em><strong>');
	$introtext = trim($introtext);

	return $introtext;
}

which is responsible of stripping the img tags, can be modified appending something like this

$introtext = preg_replace("/<a[^>]*><\\/a[^>]*>/", '', $introtext);

removing all empty hyperlinks