[BUG] Using `layoutRoot` on the parent causes degradation of performance in `Reorder` component

1. Read the FAQs 👇

✅

2. Describe the bug

Using layoutRoot on the parent causes degradation of performance in Reorder component.

3. IMPORTANT: Provide a CodeSandbox reproduction of the bug

https://codesandbox.io/p/sandbox/framer-motion-variants-forked-kwqsnd?file=%2Fsrc%2FApp.tsx

4. Steps to reproduce

Steps to reproduce the behavior:

1. Create a parent with open and closed variants with different scales.
2. Create a Reorder.Group with layout and layoutRoot properties.
3. Create a few Reorder.Item.
4. Toggle the parent's variant and observe the Reorder.Group correctly follow the parent.
5. Reorder the Reorder.Item and observe degradation in performance and jittery motion.

5. Expected behavior

Adding layoutRoot should not affect the performance of the Reorder component. If layout is causing the issue, it would be good to be able to set only layoutRoot without layout.

6. Video or screenshots

https://github.com/framer/motion/assets/455178/fe153434-a941-4c28-bec1-36da6517ac8b

7. Environment details

Google Chrome: 119.0.6045.159
MacOS: Sonoma 14.0
Framer-motion: 10.16.5
React: 18.2.0

Start with the CodeSandbox reproduction in src/App.tsx and verify the performance difference when reordering with the parent variant and Reorder.Group using layout and layoutRoot. Trace the Reorder component's layout handling, then confirm that toggling the parent and reordering items no longer causes jitter or degradation without regressing the parent transition.