[protocol] Move close channel after close topics

[0xcb9ff9]

Description

unit test exist random crash, isClosed atomic var not use CAS swap and the channel is closed before canceling the topic subscription

panic: send on closed channel

goroutine 2696 [running]:
github.com/dogechain-lab/dogechain/protocol.(*syncPeerClient).handleStatusUpdate(0xc001275680, {0xf98aa0, 0xc0039ef590}, {0xc0039fb440, 0x1484f01})
	/home/runner/work/dogechain/dogechain/protocol/client.go:217 +0x333
github.com/dogechain-lab/dogechain/network.(*topicImp).readLoop.func2()
	/home/runner/work/dogechain/dogechain/network/gossip.go:131 +0x43
created by github.com/dogechain-lab/dogechain/network.(*topicImp).readLoop
	/home/runner/work/dogechain/dogechain/network/gossip.go:124 +0x1b3
FAIL	github.com/dogechain-lab/dogechain/protocol	5.132s

Changes include

• Bugfix (non-breaking change that solves an issue)

Checklist

• I have assigned this PR to myself
• I have added at least 1 reviewer
• I have added the relevant labels

Testing

• I have tested this code with the official test suite

[DarianShawn]

LGTM.
Thanks for the work.