fix: handle non-existing getImages method in Carousel class

This commit addresses the issue where a call to the undefined method getImages on the possible false in Carousel.php was causing an error. A check is now in place before calling the method. Consequently, the phpstan-baseline.neon file has also been updated to remove the now unnecessary error suppression.

Related: #28 (closed)

.phive/phars.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <phive xmlns="https://phar.io/phive">
   <phar name="phpstan" version="1.11.1" installed="1.11.1" location="./tools/phpstan" copy="false"/>
+  <phar name="phpunit" version="^10.5.20" installed="10.5.20" location="./tools/phpunit" copy="false"/>
 </phive>