### What problem does this PR solve?
-Add Api for download "message" component output's file
-Change the attachment output type check from tuple to
dictionary,because 'attachement' is not instance of tuple
-Update the message type to message_end to avoid the problem that
content does not send an error message when the message type is ans
["data"] ["content"]
### Type of change
- [x] Bug Fix (non-breaking change which fixes an issue)
- [x] New Feature (non-breaking change which adds functionality)
8de6b97806