Remove wait deprecated API usage

Author: rajkan01

BLE_GAP/source/main.cpp

@@ -769,7 +769,7 @@ int main()
 
     while (1) {
         demo.run();
-        wait_ms(TIME_BETWEEN_MODES_MS);
+        thread_sleep_for(TIME_BETWEEN_MODES_MS);
         printf("\r\nStarting next GAP demo mode\r\n");
     };