[Feature](react-icons): Add fui-Icon className to createFluentIcon

[sopranopillow]

Describe the feature that you would like added

I am proposing to add fui-Icon to all icons. We currently add fui-Icon-<filled|regular> when we bundle icons to use for selectors to hide/show the icon, so we could extend this pattern and add a base className to help narrow selectors down to avoid something like [".${component.iconClassName} svg"]: {}

Additional context

This is currently done in product code because there's no other way to target the svg without using svg directly

Have you discussed this feature with our team

@emmayjiang

Validations

• Check that there isn't already an issue that requests the same feature to avoid creating a duplicate.

Priority

Low