Fix IPC Actions data race (ros2#147)

* Check if goal was sent through IPC before send responses
* Add intra_process_action_server_is_available API to intra-process Client


---------

Co-authored-by: Mauro Passerino <mpasserino@irobot.com>

rclcpp/include/rclcpp/experimental/action_client_intra_process_base.hpp

@@ -158,6 +158,17 @@ class ActionClientIntraProcessBase : public rclcpp::Waitable
     event_info_multi_map_.erase(goal_id);
   }
 
+  bool has_goal_id(size_t goal_id) const
+  {
+    // Check if the intra-process client has this goal_id
+    auto it = event_info_multi_map_.find(goal_id);
+    if (it != event_info_multi_map_.end()) {
+      return true;
+    }
+
+    return false;
+  }
+
 private:
   std::string action_name_;
   QoS qos_profile_;