Fix Org ID param formatting for x-sb-psc sample

[daschwanden]

What's changed, or what was fixed?

• Updated Org ID format

• If used as is the Org ID param will result into "organizations/organizations/my-org-id" since the resource "google_apigee_endpoint_attachment" "endpoint_attachment" in sb-psc-attachment module already concatenates the Org ID string to "organizations/${var.apigee_organization}"

• Passing the Project ID only (which is identical with the Org ID) is sufficient.

• [ x ] I have run all the tests locally and they all pass.

• [ x ] I have followed the relevant style guide for my changes.

[danistrebel]

Hi @daschwanden as discussed offline this should be fixed #123 Big thanks for bringing this up!