Remove useless coalescing operator on non-null return value

Signed-off-by: Côme Chilliet <come.chilliet@nextcloud.com>

lib/private/Files/Storage/Local.php

@@ -249,7 +249,7 @@ class Local extends \OC\Files\Storage\Common {
 		$fullPath = $this->getSourcePath($path);
 		if (PHP_INT_SIZE === 4) {
 			$helper = new \OC\LargeFileHelper;
-			return $helper->getFileSize($fullPath) ?? false;
+			return $helper->getFileSize($fullPath);
 		}
 		return filesize($fullPath);
 	}