check if user is joined in the room in user_can_invite

Signed-off-by: strawberry <strawberry@puppygock.gay>

src/service/rooms/state_accessor/mod.rs

@@ -142,6 +142,7 @@ impl Service {
 
 	/// Whether a user's power level is sufficient to invite other users
 	pub fn user_can_invite(&self, user_id: &UserId, room_id: &RoomId) -> Result<bool> {
+		if services().rooms.state_cache.is_joined(user_id, room_id)? {
 			self.room_state_get(room_id, &StateEventType::RoomPowerLevels, "")?
 				.map_or(Ok(false), |pdu_event| {
 					serde_json::from_str(pdu_event.content.get()).map(|content: RoomPowerLevelsEventContent| {
@@ -149,6 +150,9 @@ impl Service {
 					})
 				})
 				.map_err(|_| Error::bad_database("Invalid history visibility event in database."))
+		} else {
+			Ok(false)
+		}
 	}
 
 	/// Whether a user is allowed to see an event, based on