When the format of the response received from the outgoing webhook
server is invalid (unparsable json, or just wrong format that doesn't
translate into a dictionary etc.), a message with the error is sent to
the bot owner. We should include the actual payload to make reasonable
debugging possible.
In notify_bot_owner we have to move the `if response_content` block to
append the payload to the message whenever it was specified as an
argument to the function. It shouldn't be nested inside
`elif status_code` as before.
c95cac2dd7