Summary:
When integrating react-native into react-native-windows, we got the following build warning (which we treat as an error) when building ReactCommon: `C4715 not all control paths return a value`
This PR adds defaults to the switches to make sure every path returns a value.
See https://github.com/microsoft/react-native-windows/issues/13516
## Changelog:
[GENERAL] [FIXED] Fix "C4715 not all control paths return a value" warning in MSVC when building ReactCommon
Pull Request resolved: https://github.com/facebook/react-native/pull/45827
Test Plan: The switches are checking enums this code should never be hit unless new enum values are added.
Reviewed By: robhogan
Differential Revision: D61103286
Pulled By: NickGerleman
fbshipit-source-id: 2028cb60e0b438b9ac17a828f5e1b690052a0bec
