[EN-1450] exchange code for tns corrected

Author: iamishalkin

dxfeed/core/listeners/listener.pyx

@@ -113,7 +113,7 @@ cdef void time_and_sale_default_listener(int event_type,
                                  tns[i].event_flags,
                                  tns[i].index,
                                  tns[i].time,
-                                 tns[i].exchange_code,
+                                 unicode_from_dxf_const_string_t(&tns[i].exchange_code),
                                  tns[i].price,
                                  tns[i].size,
                                  tns[i].bid_price,