Add an indicator in the title bar if Streamer Mode is active (#4410)

src/widgets/dialogs/SettingsDialog.hpp

@@ -27,6 +27,7 @@ class PageHeader : public QFrame
 
 enum class SettingsDialogPreference {
     NoPreference,
+    StreamerMode,
     Accounts,
     ModerationActions,
 };
@@ -57,6 +58,7 @@ private:
     void selectTab(SettingsDialogTab *tab, const bool byUser = true);
     void selectTab(SettingsTabId id);
     void filterElements(const QString &query);
+    void setElementFilter(const QString &query);
 
     void onOkClicked();
     void onCancelClicked();