Add GQL mutation to update catalog resource to draft state

What does this MR do and why?

This MR adds a GraphQL mutation that updates a catalog resource to draft state. The required argument is the Global ID of the catalog resource.

The action term used is unpublish, equivalent to "update state to draft".

Resolves #428439 (closed)

How to set up and validate locally

1. Create at least one catalog resource. You can also create one in the Rails console like so:

Ci::Catalog::Resource.create(project: <YOUR-PROJECT>)

2. Update your catalog resource to published state:

catalog_resource.update!(state: :published)

2. Get the GID of that resource:

catalog_resource.to_gid

3. Go to http://gdk.test:3000/-/graphql-explorer and test the following query:

mutation {
  catalogResourceUnpublish(input: { id: "<CATALOG-RESOURCE-GID>" }) {
    errors
  }
}

4. The result should show no errors. Recheck the catalog resource's state and confirm it is now draft:

catalog_resource.reload

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #428439 (closed)