The DNS experiment could not be revoked

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Issue Description

bug report

Describe what happened (or what feature you want)

The DNS experiment could not be revoked

Describe what you expected to happen

How to reproduce it (as minimally and precisely as possible)

blade create k8s container-network dns --names tomcat-7c4d68c759-9qqxm --kubeconfig ~/.kube/config --domain www.xx.com --ip 10.10.10.1 --container-names tomcat

blade destroy xxxx

Tell us your environment

chaosblade 1.6.1

Anything else we need to know?

Because the DNS experiment is implemented by modifying /etc/hosts, recovery should not enter the MNT namespace of the pause container.