Update expectation for return type of getCustomAttributes

Author: alexander-aleman

dev/tests/integration/testsuite/Magento/Swatches/Block/Product/ListProductTest.php

@@ -166,7 +166,7 @@ private function assertProductImage(array $images, string $area, array $expectat
         $this->updateProductImages($images);
         $productImage = $this->listingBlock->getImage($this->productRepository->get('configurable'), $area);
         $this->assertInstanceOf(Image::class, $productImage);
-        $this->assertEquals($productImage->getCustomAttributes(), '');
+        $this->assertEquals($productImage->getCustomAttributes(), []);
         $this->assertEquals($productImage->getClass(), 'product-image-photo');
         $this->assertEquals($productImage->getRatio(), 1.25);
         $this->assertEquals($productImage->getLabel(), $expectation['label']);