feat(app-backend): key circuit breaker by URI path pattern (#6383)

* feat(app-lib): split `FetchFence` on base URI path

* chore: fmt

* fix(app-lib): fix test timing

packages/app-lib/src/state/instances/content.rs

@@ -895,6 +895,7 @@ async fn get_modpack_identifiers(
         &[&primary_file.url],
         primary_file.hashes.get("sha1").map(|s| s.as_str()),
         Some(&download_meta),
+        None,
         fetch_semaphore,
         pool,
     )