Duplicate resources are created by default

[jozefizso]

When modeling existing Sentry org and projects to terraform the plan will by default create all the resources as new entities in Sentry. As the Sentry UI does not show the internal ID for the resources the org will have duplicate projects which are hard to distinguish from the original ones.

Unless we manually import each resource into the TF state, the provider will create duplicates even when slugs are the same.

It would be more intuitive when Sentry provider would not duplicate these resources and it would use the slug as identifier to match resources in .tf files to the entities on the server.