This function allows users to stop a broadcast. A broadcast can be stopped if it is in any of the following status: "start", "sent" or "pause".
* action: STOP_BROADCAST.
* broadcast_id: broadcast ID.
The response contains the following attribute:
* msg: indicates that the broadcast has been stopped successfully.
The following example shows a successful HTTP GET request and response.
<result tftype='1' infotype='0'>