feat: leave workspace api (#4942)

* feat: leave workpspace event

* feat: add leave workspace event

---------

Co-authored-by: Lucas.Xu <lucas.xu@appflowy.io>

frontend/rust-lib/flowy-user-pub/src/cloud.rs

@@ -234,6 +234,10 @@ pub trait UserCloudService: Send + Sync + 'static {
     workspace_id: &str,
     objects: Vec<UserCollabParams>,
   ) -> FutureResult<(), FlowyError>;
+
+  fn leave_workspace(&self, workspace_id: &str) -> FutureResult<(), FlowyError> {
+    FutureResult::new(async { Ok(()) })
+  }
 }
 
 pub type UserUpdateReceiver = tokio::sync::mpsc::Receiver<UserUpdate>;