[FEATURE] React 19 Support

[beeme1mr]

Requirements

Ensure the OpenFeature React SDK supports React 19. This will likely require no code changes but should be confirmed now that React 19 is GA.

[juandelacruz23]

It seems that the mechanism to suspend used in https://github.com/open-feature/js-sdk/blob/main/packages/react/src/internal/suspense.ts is now legacy and not recommended anymore. Should the implementation change to account for that?

[beeme1mr]

We should eventually but we'll still need to support older version of React for the time being.