Summary:
Fix warnings about implicit type truncation.
## Changelog
[Internal] [Fixed] - Fix various C++ warnings
Pull Request resolved: https://github.com/facebook/react-native/pull/31002
Test Plan:
Almost all the changes here are simply making explicit conversions which are already occurring. With the exception of a couple of constants being changed from doubles to floats.
With these changes I am able to remove a bunch of warning suppressions in react-native-windows.
Reviewed By: shergin
Differential Revision: D26900502
Pulled By: rozele
fbshipit-source-id: d5e415282815c2212a840a863713287bbf118c10