refactor get_room_topic into 1 single function

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

src/service/rooms/spaces/mod.rs

@@ -17,7 +17,6 @@ use ruma::{
 			avatar::RoomAvatarEventContent,
 			create::RoomCreateEventContent,
 			join_rules::{AllowRule, JoinRule, RoomJoinRulesEventContent, RoomMembership},
-			topic::RoomTopicEventContent,
 		},
 		space::child::{HierarchySpaceChildEvent, SpaceChildEventContent},
 		StateEventType,
@@ -573,15 +572,7 @@ impl Service {
 			topic: services()
 				.rooms
 				.state_accessor
-				.room_state_get(room_id, &StateEventType::RoomTopic, "")?
-				.map_or(Ok(None), |s| {
-					serde_json::from_str(s.content.get())
-						.map(|c: RoomTopicEventContent| Some(c.topic))
-						.map_err(|_| {
-							error!("Invalid room topic event in database for room {}", room_id);
-							Error::bad_database("Invalid room topic event in database.")
-						})
-				})
+				.get_room_topic(room_id)
 				.unwrap_or(None),
 			world_readable: services().rooms.state_accessor.is_world_readable(room_id)?,
 			guest_can_join: services().rooms.state_accessor.guest_can_join(room_id)?,