1. Reassgin now will assign to the original Node if no other nodes
avaliable
2. Make AddNode balance async: ToRealse + Reassign
See also: #16114, #17270
Signed-off-by: yangxuan <xuan.yang@zilliz.com>
If we start up 2 data nodes and one of them crashes. We expect that all
channels of crashed node will be allcoated to the alive node. But now we
discover that these channels are lost after data node crash. The reason
is we pass a NodeInfo with empty channel info. We fix it and improve log
print.
issue: #6501
Signed-off-by: sunby <bingyi.sun@zilliz.com>
