Add Uniqueness Check for nftMetadataHash During IP Registration

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Description and Context

Currently, the same external IP can be registered as IP an unlimited number of times. We’ve received a request to implement a mechanism that checks the uniqueness of the content, allowing it to be registered as IP only if it is unique.

Suggested Solution

To address this, we can introduce a check in the existing periphery functions responsible for IP registration. The check will ensure that an IP is only registered if the nftMetadataHash (part of the WorkflowStructs.IPMetadata struct) does not already exist. If the content is not unique, the function will return the ID of the already registered IP.

This check will be disabled by default and can be enabled by passing a boolean flag set to true.