Remove deprecated ShadowNode type aliases (#55687)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/55687

## Changelog:
[General] [Breaking]: Removing deprecated type aliases. Use the type directly.

Remove deprecated type aliases from ShadowNode that were scheduled for deletion in 0.84:
- `ShadowNode::Shared` → use `std::shared_ptr<const ShadowNode>`
- `ShadowNode::Weak` → use `std::weak_ptr<const ShadowNode>`
- `ShadowNode::Unshared` → use `std::shared_ptr<ShadowNode>`
- `ShadowNode::ListOfShared` → use `std::vector<std::shared_ptr<const ShadowNode>>`
- `ShadowNode::ListOfWeak` → use `std::vector<std::weak_ptr<const ShadowNode>>`

Reviewed By: lenaic

Differential Revision: D90331085

fbshipit-source-id: bd4f60b5b2133b47aa66246161387c1d7459f2fd