Fixed more compile time errors

src/service/rooms/edus/presence/data.rs

@@ -1,6 +1,7 @@
 use std::collections::HashMap;
 
 use ruma::{UserId, RoomId, events::presence::PresenceEvent};
+use crate::Result;
 
 pub trait Data {
     /// Adds a presence event which will be saved until a new event replaces it.