Skip container annotations is not working for me.

**What happened**:
I have added below annotation as mentioned in document but still AWS_ROLE_ARN and AWS_WEB_IDENTITY_TOKEN_FILE environmental variable is getting added to the ignored contaIners.

```
apiVersion: v1
kind: Pod
metadata:
annotations:
eks.amazonaws.com/skip-containers: jaeger-agent,istio-proxy
```

**Environment**:
- AWS Region: us-east-1
- EKS Platform version: eks.3
- Kubernetes version : 1.17

The issue names no source file or test. Reproduce the annotation behavior on the stated EKS and Kubernetes versions, then trace how the webhook handles eks.amazonaws.com/skip-containers; done means AWS_ROLE_ARN and AWS_WEB_IDENTITY_TOKEN_FILE are absent from the listed containers.

Written by the indexing model from the issue text.