Update thread archive status when sending media.

app/src/main/java/org/thoughtcrime/securesms/sms/MessageSender.java

@@ -151,6 +151,7 @@ public class MessageSender {
 
       sendMediaMessage(context, recipient, forceSms, messageId, Collections.emptyList());
       onMessageSent();
+      threadDatabase.update(threadId, true);
 
       return allocatedThreadId;
     } catch (MmsException e) {
@@ -194,6 +195,7 @@ public class MessageSender {
 
       sendMediaMessage(context, recipient, false, messageId, jobIds);
       onMessageSent();
+      threadDatabase.update(threadId, true);
 
       return allocatedThreadId;
     } catch (MmsException e) {