pushStackTop method
Implementation
void pushStackTop({required Widget page}) {
  if (_pages.isNotEmpty) {
    _pages.removeWhere(
        (element) => element.child.runtimeType == page.runtimeType);
  }
  push(page: page);
}
void pushStackTop({required Widget page}) {
  if (_pages.isNotEmpty) {
    _pages.removeWhere(
        (element) => element.child.runtimeType == page.runtimeType);
  }
  push(page: page);
}