Fix opening message menus for popup windows

We were previously assuming that we always want to parent these menus to
RoomPage, but that only exists on the main window. If you tried to open
the menu for say - the search window - then it would confusingly still
open on the main menu.

Thankfully the way to fix this is simple, by passing a parent QtObject
around.

src/app/roommanager.cpp

@@ -282,14 +282,15 @@ void RoomManager::viewEventSource(const QString &eventId)
     Q_EMIT showEventSource(eventId);
 }
 
-void RoomManager::viewEventMenu(const RoomEvent *event, NeoChatRoom *room, const QString &selectedText, const QString &hoveredLink)
+void RoomManager::viewEventMenu(QObject *parent, const RoomEvent *event, NeoChatRoom *room, const QString &selectedText, const QString &hoveredLink)
 {
     if (!event) {
         qWarning() << "Tried to open event menu with empty event";
         return;
     }
 
-    Q_EMIT showDelegateMenu(event->id(),
+    Q_EMIT showDelegateMenu(parent,
+                            event->id(),
                             room->qmlSafeMember(event->senderId()),
                             MessageComponentType::typeForEvent(*event),
                             EventHandler::plainBody(room, event),