WIP: Give worktrees a reference to the UserStore

This will allow them to fetch user data when peers are added or removed. Still work to do though.

crates/project_panel/src/lib.rs

@@ -621,6 +621,7 @@ mod tests {
             Project::new(
                 params.languages.clone(),
                 params.client.clone(),
+                params.user_store.clone(),
                 params.fs.clone(),
             )
         });