Revert "Dispose scaffold drawers. (#108234)"

This reverts commit 527ee1d7286e5e075e75b4915198229dd8af18fe.
diff --git a/packages/flutter/lib/src/material/scaffold.dart b/packages/flutter/lib/src/material/scaffold.dart
index e02d44d..4b4ab9e 100644
--- a/packages/flutter/lib/src/material/scaffold.dart
+++ b/packages/flutter/lib/src/material/scaffold.dart
@@ -2578,8 +2578,6 @@
     _floatingActionButtonMoveController.dispose();
     _floatingActionButtonVisibilityController.dispose();
     _scaffoldMessenger?._unregister(this);
-    _drawerOpened.dispose();
-    _endDrawerOpened.dispose();
     super.dispose();
   }