fix php_url_encode_hash_ex call for 8.3

[remicollet]

From UPGRADING.INTERNALS

   - The PHPAPI php_url_encode_hash_ex() function has had its signature change
     from:
     PHPAPI void php_url_encode_hash_ex(HashTable *ht, smart_str *formstr,
                                const char *num_prefix, size_t num_prefix_len,
                                const char *key_prefix, size_t key_prefix_len,
                                const char *key_suffix, size_t key_suffix_len,
                                zval *type, const char *arg_sep, int enc_type);
     to:
     PHPAPI void php_url_encode_hash_ex(HashTable *ht, smart_str *formstr,
                                const char *num_prefix, size_t num_prefix_len,
                                const zend_string *key_prefix,
                                zval *type, const zend_string *arg_sep, int enc_type);
     The change to use zend_string prevent the computation of the arg_sep
     length at each call. The key_suffix parameter was dropped as it was a
     constant value and depended on the key_prefix parameter to not be NULL.