Fix adding redundant attributes to the schemas response

[amanda-ariyaratne]

Purpose

In the /configs/schemas API, attributes are added to and removed from the default profile based on the schemas.profile configuration. If an attribute that is already present in a schema is added again to the same schema, the attribute is duplicated. This PR fixes the above by taking the unique attributes.

Related Issues

• Revamp SCIM schemas in IS product-is#20850

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