MAGECLOUD-4080: Update default example in magento-vars.php (#6508)

Author: NadiyaS

src/cloud/project/project-multi-sites.md

@@ -201,19 +201,11 @@ To pass variables using the `magento-vars.php` file:
        if (!isset($_SERVER['HTTP_HOST'])) {
            return false;
        }
-       return strpos(str_replace('---', '.', $_SERVER['HTTP_HOST']), $host) === 0;
+       return $_SERVER['HTTP_HOST'] === $host;
    }
    ```
    {:.no-copy}
 
-1. Change the `return` line in the `function` block.
-
-   ```diff
-   -   return strpos(str_replace('---', '.', $_SERVER['HTTP_HOST']), $host) === 0;
-   +   return $_SERVER['HTTP_HOST'] ===  $host;
-   ```
-   {:.no-copy}
-
 1. Move the commented `if` block so that it is _after_ the `function` block and no longer commented.
 
    ```php