wifi: iwlwifi: tests: check configs are not duplicated

Add a kunit test to check that all (used) config structs
are not duplicated, ignoring the name since that can be
handled differently via the dev-info list.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250502155404.0cfd9fb8322e.I9567b839405be8d1e4be0bfca7a17b5d222b0158@changeid