core: support removing property from existing set of styles

[micahgodbolt]

If a component is already setting the font-family, there is no way to completely remove the font-family property. The only option is to set the font-family to a new, valid value. There is currently no way to completely remove the font-family property.

current behavior

.a { font-family: 'arial'}
add griffel override
.b { font-family: 'inherit' }

desired behavior

.a { font-family: 'arial'}
add griffel override
// no font family declaration