Implement new argument differently

So it doesn't break backwards compatibility, as requested in
#48684 (comment)

src/Symfony/Component/DomCrawler/Crawler.php

@@ -561,9 +561,13 @@ public function text(string $default = null, bool $normalizeWhitespace = true):
 
     /**
      * Returns only the inner text that is the direct descendent of the current node, excluding any child nodes.
+     *
+     * @param bool $normalizeWhitespace
      */
-    public function innerText(bool $normalizeWhitespace = true): string
+    public function innerText(): string
     {
+        $normalizeWhitespace = 1 <= func_num_args() ? func_get_arg(0) : true;
+
         foreach ($this->getNode(0)->childNodes as $childNode) {
             if (\XML_TEXT_NODE === $childNode->nodeType && '' !== trim($childNode->nodeValue)) {
                 return $normalizeWhitespace ? $this->normalizeWhitespace($childNode->nodeValue) : $childNode->nodeValue;