Core: Make PagedSettings autoapply by default in the base

Instead of relying (and forgetting...) it in all derived clases.

Change-Id: I5d1dea0ace420d464c39c192278ae6e5db01de90
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

src/plugins/coreplugin/dialogs/ioptionspage.cpp

@@ -303,6 +303,10 @@ QIcon IOptionsPageProvider::categoryIcon() const
 
 // PagedSettings
 
-PagedSettings::PagedSettings() = default;
+PagedSettings::PagedSettings()
+{
+    setSettings(this);
+    setAutoApply(false);
+}
 
 } // Core