Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/52212
Correcting some C++ imports that show up when build with Xcode 26:
- Missing `<string>` imports.
- `<tgmath.h>` is a deprecated C++ header file, which in this case can be substituted with `<cmath>`.
## Changelog: [Internal]
[iOS][Fixed] - Fix deprecated C++ imports
Reviewed By: zhenma
Differential Revision: D77192276
fbshipit-source-id: 30c836947cb3eb54f6e7ac42b87fd2493334a4f4