NetBox Device Type Library: PR-controllable upstream clone URL (NETBOX_DT_LIBRARY_URL) enables SSRF and test-data substitution from CI

NetBox Device Type Library is a collection of community-sourced device type definitions for import into NetBox. In the affected repository revisions, NETBOX_DT_LIBRARY_URL in tests/test_configuration.py is a free-form tracked constant that an unauthenticated pull-request author can change before the validation test harness runs. During pytest collection, tests/definitions_test.py passes the value to Repo.clone_from and create_remote("upstream").fetch(), causing blind Git smart-HTTP requests to an attacker-selected host or loading attacker-controlled tests/known-*.json validation caches. The blind request cannot set arbitrary metadata-service headers or return response bodies, and this path does not execute remote Git hooks, but substituted known data can bypass slug, module, and rack uniqueness validation. This vulnerability is fixed in commit 8980c690097e92f5028c7e6df402b327d827ecd5.