Since we are progressively descouraging the use of the SubHeader block, we shoudl remove it from the vailable ones, to avoid folks to use it further.

Full report on blocks usage (see Subheader on Column L) >> https://docs.google.com/spreadsheets/d/1uAmZLIWYsxrBByqbhoF_vVtSM7WGebYWIc0xftPRPwE/edit#gid=1244049503