DS - Use preprocessors to filter out VADS web font tokens

[narin]

Description

This ticket is blocked by the ticket to update style-dictionar to 4.0. (#507)

Somewhere between css-library versions ^0.11.0 and ^0.16.0, the VADS web team added some font tokens that have conflicting names with our mobile font tokens. Since font tokens won't be shared between web and mobile, we want to exclude them from our token build. We are already doing so with the filter/fonts/is-mobile-font filter, but we have to declare that filter for several files in our style dictionary config which isn't ideal.

style-dictionary 4.0 introduced preprocessors which should allow us to remove all VADS Web font tokens before they are run through our build and simplify our config code.

Acceptance Criteria

• Once style-dictionary has been updated to 4.0, replace is-mobile-font filter with preprocessor
  Accessibility Requirements