Projected volumeMount missing

**What happened**:
We created a pod with a `iam.amazonaws.com/role:` annotation. The environment variables `AWS_ROLE_ARN` and `AWS_WEB_IDENTITY_TOKEN_FILE` are created. The volume `aws-iam-token` is also added to the pod. But the volumeMount `aws-iam-token` is missing. Other pods in the same namespace with the same service account but created by a different deployment are created with the volume mount.

**What you expected to happen**:

The volumeMount `aws-iam-token` is created alongside the environment variables and the volume.

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

**Anything else we need to know?**:

**Environment**:
- AWS Region: eu-central-1
- EKS Platform version (if using EKS, run `aws eks describe-cluster --name --query cluster.platformVersion`): "eks.3"
- Kubernetes version (if using EKS, run `aws eks describe-cluster --name --query cluster.version`): "1.17"
- Webhook Version:

Start by reproducing the pod mutation described for the AWS IAM role annotation and compare it with a working pod using the same service account. Inspect the webhook's handling of the aws-iam-token volume, environment variables, and volumeMount; done means the expected volumeMount is added alongside the existing injected resources. The issue does not name source files, tests, or a webhook version.

Written by the indexing model from the issue text.