make efs attachable for stateful example

[casualuser]

Description

shared efs storage in stateful example doesn't work without that workaround described in #1197 (comment)
it looks wise for me to fix the example in any way

Motivation and Context

• Resolves Mount issues with module aws_efs_csi_driver #1197

How was this change tested?

• Yes, I have tested the PR using my local account setup (Provide any test evidence report under Additional Notes)
• Yes, I have updated the docs for this feature
• Yes, I ran pre-commit run -a with this PR

Additional Notes

literally nothing to add

[bryantbiggs]

can you provide a reproduction please

[github-actions]

This PR has been automatically marked as stale because it has been open 30 days
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[github-actions]

Pull request closed due to inactivity.

[Almenon]

@bryantbiggs the current stateful example would be the reproduction, right? I just ran into this issue and the change in this PR fixed it.

Relevant: kubernetes-sigs/aws-efs-csi-driver#1169

[bryantbiggs]

We need two things for issues (as defined in the issue templates):

1. Description of the issue and any error output
2. A minimum deployable reproduction that demonstrates the issue described in point 1

[Almenon]

I was saying that the current stateful pattern at https://github.com/aws-ia/terraform-aws-eks-blueprints/tree/main/patterns/stateful would count as satisfying #2, as it is likely broken and demonstrates the issue.