Fix UserSettingsModel and Communities singleton instantiation

src/InviteesModel.h

@@ -6,6 +6,7 @@
 #define INVITEESMODEL_H
 
 #include <QAbstractListModel>
+#include <QQmlEngine>
 #include <QVector>
 
 #include "timeline/TimelineModel.h"
@@ -34,6 +35,8 @@ private:
 class InviteesModel final : public QAbstractListModel
 {
     Q_OBJECT
+    QML_ELEMENT
+    QML_UNCREATABLE("")
 
     Q_PROPERTY(int count READ rowCount NOTIFY countChanged)
     Q_PROPERTY(TimelineModel *room READ room CONSTANT)

src/MemberList.h

@@ -5,6 +5,7 @@
 #pragma once
 
 #include <QAbstractListModel>
+#include <QQmlEngine>
 #include <QSortFilterProxyModel>
 
 #include <mtx/events/power_levels.hpp>
@@ -79,6 +80,8 @@ private:
 class MemberList final : public QSortFilterProxyModel
 {
     Q_OBJECT
+    QML_ELEMENT
+    QML_UNCREATABLE("")
 
     Q_PROPERTY(QString roomName READ roomName NOTIFY roomNameChanged)
     Q_PROPERTY(int memberCount READ memberCount NOTIFY memberCountChanged)

src/UserSettingsPage.h

@@ -456,6 +456,7 @@ class UserSettingsModel : public QAbstractListModel
 {
     Q_OBJECT
     QML_ELEMENT
+    QML_SINGLETON
 
     enum Indices
     {

src/timeline/CommunitiesModel.h

@@ -154,7 +154,7 @@ public:
         void restoreCollapsed();
     };
 
-    CommunitiesModel(QObject *parent = nullptr);
+    CommunitiesModel(QObject *parent);
 
     static CommunitiesModel *create(QQmlEngine *qmlEngine, QJSEngine *)
     {