Fix: trigger gift wrap subscription when getting conversations

getConversations was returning an empty observable because
subscribeToGiftWraps() was never called. Now triggers the subscription
when the inbox is opened.

src/lib/chat/adapters/nip-17-adapter.ts

@@ -419,6 +419,9 @@ export class Nip17Adapter extends ChatProtocolAdapter {
       return new BehaviorSubject([]);
     }
 
+    // Start fetching gift wraps from inbox relays
+    this.subscribeToGiftWraps(activePubkey);
+
     return this.giftWraps$.pipe(
       map((giftWraps) => {
         // Group rumors by conversation