Fix review issues, Remove EventHash's in prev/auth_events in StateEvent

The latest state-res crate uses ruma's PduRoomV3 PDU's which don't have
tuples of (EventId, EventHashs) like previous versions did (this was
left from rebasing onto master). The Media DB
now takes an optional content_type like the updated ruma structs.

src/server_server.rs

@@ -419,7 +419,7 @@ pub async fn send_transaction_message_route<'a>(
         }
     }
 
-    // TODO: For RoomVersion6 we must check that Raw<..> is canonical do we?
+    // TODO: For RoomVersion6 we must check that Raw<..> is canonical do we anywhere?
     // SPEC:
     // Servers MUST strictly enforce the JSON format specified in the appendices.
     // This translates to a 400 M_BAD_JSON error on most endpoints, or discarding of
@@ -554,7 +554,7 @@ pub async fn send_transaction_message_route<'a>(
                 // TODO we may not want the auth events chained in here for resolution?
                 their_current_state
                     .iter()
-                    .map(|(_id, v)| ((v.kind(), v.state_key()), v.event_id().clone()))
+                    .map(|(_id, v)| ((v.kind(), v.state_key()), v.event_id()))
                     .collect::<BTreeMap<_, _>>(),
             ],
             Some(