Ensure device links are always up to date

SignalServiceKit/src/Loki/API/LokiLongPoller.swift

@@ -83,8 +83,13 @@ public final class LokiLongPoller : NSObject {
         return LokiAPI.getRawMessages(from: target, usingLongPolling: true).then(on: DispatchQueue.global()) { [weak self] rawResponse -> Promise<Void> in
             guard let strongSelf = self, !strongSelf.hasStopped else { return Promise.value(()) }
             let messages = LokiAPI.parseRawMessagesResponse(rawResponse, from: target)
+            let hexEncodedPublicKeys = Set(messages.compactMap { $0.source })
+            let promises = hexEncodedPublicKeys.map { LokiAPI.getDestinations(for: $0) }
+            return when(resolved: promises).then(on: DispatchQueue.global()) { _ -> Promise<Void> in
+                guard let strongSelf = self, !strongSelf.hasStopped else { return Promise.value(()) }
                 strongSelf.onMessagesReceived(messages)
                 return strongSelf.longPoll(target, seal: seal)
             }
         }
+    }
 }

SignalServiceKit/src/Messages/OWSMessageManager.m

@@ -1474,8 +1474,6 @@ NS_ASSUME_NONNULL_BEGIN
         }
     } else {
         
-        // TODO: Do we need to fetch the device mapping here?
-        
         // Loki: A message from a secondary device should appear as if it came from the primary device; the underlying
         // friend request logic, however, should still be specific to the secondary device.