Make React template work with Additional Panels

[justintaylor-dev]

See full bug issue here:

https://forums.creativeclouddeveloper.com/t/additional-uxp-panel-not-loading-in-react-properly/7972

And proposed workaround:

https://forums.creativeclouddeveloper.com/t/ruxp-react-components-for-declarative-uxp-entry-points/7527/4

Other versions:

https://forums.creativeclouddeveloper.com/t/additional-uxp-panel-not-loading-in-react-properly/7972/4