yuzu: Move disable_web_applet to UISettings

src/yuzu/main.h

@@ -400,9 +400,6 @@ private:
     // Last game booted, used for multi-process apps
     QString last_filename_booted;
 
-    // Disables the web applet for the rest of the emulated session
-    bool disable_web_applet{};
-
     // Applets
     QtSoftwareKeyboardDialog* software_keyboard = nullptr;