当 spec.features.containerRuntime 不存在时无法确定容器运行时到底是什么

[jo-hnny]

What happened:
当 spec.features.containerRuntime 不存在时，新版本的集群运行时为containerd，老版本为docker，不统一

What you expected to happen:
最好是所有集群都含有spec.features.containerRuntime 字段，以确保集群运行时组件是显示确定的

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

Anything else we need to know?:

Environment:

• TKE version:
• Global or business cluster:
• Kubernetes version (use kubectl version):
• Install addons:
• Others:

[Huimintai]

PR to fix this issue here: #1553