fix(date-picker): remove outline for header actions (#11369)

**Related Issue:** #11371 

## Summary

Removes outline for header actions which is causing transition on focus
shift.

This is introduced with
#10836 where outline
exclusion from transition is ignored in Tailwind util.

BEGIN_COMMIT_OVERRIDE
omitted from changelog
END_COMMIT_OVERRIDE

packages/calcite-components/src/components/date-picker-month-header/date-picker-month-header.scss

@@ -63,7 +63,6 @@
     items-center
     justify-center
     border-none
-    outline-none
     transition-default 
     w-full 
     h-full;