Avoid broadcasting SaveBuffer in response to a client's save request

The host will send a `SaveBuffer` message anyway and this prevents re-querying
the database, which could cause two `BufferSaved` messages to race and, as a
result, cause guest to apply them in the wrong order.

crates/collab/src/rpc.rs

@@ -228,7 +228,7 @@ impl Server {
             .add_message_handler(update_buffer_file)
             .add_message_handler(buffer_reloaded)
             .add_message_handler(buffer_saved)
-            .add_request_handler(save_buffer)
+            .add_request_handler(forward_project_request::<proto::SaveBuffer>)
             .add_request_handler(get_users)
             .add_request_handler(fuzzy_search_users)
             .add_request_handler(request_contact)
@@ -1591,51 +1591,6 @@ where
     Ok(())
 }
 
-async fn save_buffer(
-    request: proto::SaveBuffer,
-    response: Response<proto::SaveBuffer>,
-    session: Session,
-) -> Result<()> {
-    let project_id = ProjectId::from_proto(request.project_id);
-    let host_connection_id = {
-        let collaborators = session
-            .db()
-            .await
-            .project_collaborators(project_id, session.connection_id)
-            .await?;
-        collaborators
-            .iter()
-            .find(|collaborator| collaborator.is_host)
-            .ok_or_else(|| anyhow!("host not found"))?
-            .connection_id
-    };
-    let response_payload = session
-        .peer
-        .forward_request(session.connection_id, host_connection_id, request.clone())
-        .await?;
-
-    let mut collaborators = session
-        .db()
-        .await
-        .project_collaborators(project_id, session.connection_id)
-        .await?;
-    collaborators.retain(|collaborator| collaborator.connection_id != session.connection_id);
-    let project_connection_ids = collaborators
-        .iter()
-        .map(|collaborator| collaborator.connection_id);
-    broadcast(
-        Some(host_connection_id),
-        project_connection_ids,
-        |conn_id| {
-            session
-                .peer
-                .forward_send(host_connection_id, conn_id, response_payload.clone())
-        },
-    );
-    response.send(response_payload)?;
-    Ok(())
-}
-
 async fn create_buffer_for_peer(
     request: proto::CreateBufferForPeer,
     session: Session,