google_chat_ros: enable to get therad_name message result

[k-okada]

@mqcmd196 This is a modification to reply messages in the same thread like this

instead of creating a new thread like this one.

One strategy is to pass SimpleActionClient to the function, as in this PR modification.

(setq action goal name "google_chat_ros/send")
(setq ac (instance ros::simple-action-client :init action-goal-name google_chat_ros::SendMessageAction)))
(send-google-chat-text "spaces/AAAARE9CrfA" "Hello" :ac ac)
(send-google-chat-text "spaces/AAAARE9CrfA" "World" :thread-name (send (send ac :get-result) :message_result :thread_name) :ac ac)

Another solution would be to return the result of the message like k-okada@e9a4904 and write code like this

(setq r (send-google-chat-text "spaces/AAAARE9CrfA" "Hello"))
(send-google-chat-text "spaces/AAAARE9CrfA" "World" :thread-name (send r :message_result :thread_name)).

Which would be better? Or is there another way?

[mqcmd196]

@k-okada
I think

Another solution would be to return the result of the message like k-okada@e9a4904 and write code like this

is better because the eus function is designed to be usable without knowing the detailed message specifications.