Add unit test - subpath pattern, repeated elements

[seanzatzdev-amazon]

Is this a bug fix or adding new feature?
Adds new unit test.
What is this PR about? / Why do we need it?
This adds a unit test for the subpath pattern to test if repeated elements work correctly, with repeated elements referring to using elements such as the PVC name multiple times in the subpath pattern.

The reason for this unit test is to ensure storage classes which use elements such as the PVC name multiple times in their subpath pattern do not encounter any errors.

What testing is done?
Unit tests ran successfully.

[k8s-ci-robot]

Hi @seanzatzdev-amazon. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[mskanth972]

/ok-to-test

[Ashley-wenyizha]

/lgtm

[Ashley-wenyizha]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Ashley-wenyizha, seanzatzdev-amazon

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