Add sm size variant to Heading

[GuillaumeRx]

This adds a new size variant to the Heading component sm. It is the default size of the heading

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.45%. Comparing base (1251f80) to head (bd2b1c6).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2831   +/-   ##
=======================================
  Coverage   94.45%   94.45%           
=======================================
  Files         484      484           
  Lines       10337    10337           
  Branches     1575     1575           
=======================================
  Hits         9764     9764           
  Misses        573      573           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.