Added Dek Registry topic roll binding to CP RBAC demo

[MINHN98]

Description

• Add roll binding for the _dek_registry_keys so that SR with DEK Registry can create the topic on startup.

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[cla-assistant[bot]]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}