Improve syncing of in-memory expirationStartTimestamp

Co-authored-by: trevor-signal <131492920+trevor-signal@users.noreply.github.com>

ts/sql/Interface.ts

@@ -372,6 +372,7 @@ export type GetUnreadByConversationAndMarkReadResultType = Array<
     | 'type'
     | 'readStatus'
     | 'seenStatus'
+    | 'expirationStartTimestamp'
   >
 >;
 

ts/util/markConversationRead.ts

@@ -107,7 +107,14 @@ export async function markConversationRead(
       );
       // we update the in-memory MessageModel with fresh read/seen status
       if (message) {
-        message.set(pick(messageSyncData, 'readStatus', 'seenStatus'));
+        message.set(
+          pick(
+            messageSyncData,
+            'readStatus',
+            'seenStatus',
+            'expirationStartTimestamp'
+          )
+        );
       }
 
       const {