redo log is not cleaned up when removing a paused changefeed

[amyangfei]

What did you do?

• create a chagnefeed with redo log enabled
• pause the changefeed
• remove the changefeed

What did you expect to see?

redo log is auto cleaned after changefeed is removed

What did you see instead?

redo log is not removed

Versions of the cluster

Upstream TiDB cluster version (execute SELECT tidb_version(); in a MySQL client):

(paste TiDB cluster version here)

Upstream TiKV version (execute tikv-server --version):

(paste TiKV version here)

TiCDC version (execute cdc version):

v5.3.0