remove uses of ShadowNode::Shared from ShadowNode.cpp (#52422)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/52422

changelog: [internal]

In https://github.com/facebook/react-native/pull/52393 not all uses of ShadowNode::Shared were removed. Github CI fails if a deprecated API is used. Let's remove the last uses.

Reviewed By: cortinico

Differential Revision: D77790411

fbshipit-source-id: 6fbbbffaa784de1f0939d1032dc7ea6586f2ce7d