fix(hydra): removes duplicated volumeMounts yaml int automigrate init container

This fixes duplicated volumeMounts in the hydra migrate init container which causes the install to fail when

automigration:
        enabled: true
        type: initContainer

Checklist

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[ ] I have referenced an issue containing the design document if my change introduces a new feature.
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[ ] I have added tests that prove my fix is effective or that my feature works.
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