title_bar: Show the plan from the CloudUserStore (#35401)

This PR updates the user menu in the title bar to show the plan from the
`CloudUserStore` instead of the `UserStore`.

We're still leveraging the RPC connection to listen for `UpdateUserPlan`
messages so that we can get live-updates from the server, but we are
merely using this as a signal to re-fetch the information from Cloud.

Release Notes:

- N/A

crates/collab/src/tests/test_server.rs

@@ -282,7 +282,8 @@ impl TestServer {
             .register_hosting_provider(Arc::new(git_hosting_providers::Github::public_instance()));
 
         let user_store = cx.new(|cx| UserStore::new(client.clone(), cx));
-        let cloud_user_store = cx.new(|cx| CloudUserStore::new(client.cloud_client(), cx));
+        let cloud_user_store =
+            cx.new(|cx| CloudUserStore::new(client.cloud_client(), user_store.clone(), cx));
         let workspace_store = cx.new(|cx| WorkspaceStore::new(client.clone(), cx));
         let language_registry = Arc::new(LanguageRegistry::test(cx.executor()));
         let session = cx.new(|cx| AppSession::new(Session::test(), cx));