Revamp react-tokens logic

Describe the enhancement or change
Our token generation in the react-tokens package needs to be reworked as the logic we use to determine css var values doesn't match 1:1 with how that value will be determined in browser, this can lead to build breaking bugs with recursively defined values.

We've implemented a temporary fix for this, but it is still not optimal as differences in behavior could occur if a var is defined multiple times in a stylesheet. Ideally we should only parse the css within the root selector of the stylesheet.

Additionally, core currently has to add some variables to the root scope for the sole purpose of having the token created in react-tokens, ideally this will not be required in the future.

Jira Issue: PF-92

Comienza localizando el paquete react-tokens y su solución temporal para la generación de tokens; después, inspecciona cómo core añade variables al ámbito raíz. Compara la resolución de variables CSS del paquete con el comportamiento del navegador, especialmente en el caso de variables definidas recursivamente o varias veces. La tarea estará completada cuando el análisis del ámbito raíz coincida con la resolución del navegador y core ya no necesite variables adicionales únicamente para crear tokens.