remote: Fix incorrect default repository selection when using remote (#41698)

If I understand this correctly: The `active_repo_id` uses
`get_or_insert_with`, which makes it dependent on the `RepositoryAdded`
event sequence. To ensure correct initialization of the `active_repo_id`
on the remote side, the first local `RepositoryAdded` event must
synchronously send an `UpdateRepository` to `updates_tx`.

Closes #30694

Release Notes:

- Fixed incorrect default repository selection when using remote

crates/project/src/git_store.rs

@@ -1268,6 +1268,12 @@ impl GitStore {
                         git_store,
                         cx,
                     );
+                    if let Some(updates_tx) = updates_tx.as_ref() {
+                        // trigger an empty `UpdateRepository` to ensure remote active_repo_id is set correctly
+                        updates_tx
+                            .unbounded_send(DownstreamUpdate::UpdateRepository(repo.snapshot()))
+                            .ok();
+                    }
                     repo.schedule_scan(updates_tx.clone(), cx);
                     repo
                 });