feat(promotion, dashboard, core-flows, cart, types, utils, medusa): tax inclusive promotions (#12412)

* feat: tax inclusive promotions

* feat: add a totals test case

* feat: add integration test

* chore: changeset

* fix: typo

* chore: refactor

* fix: tests

* fix: rest of buyget action tests

* fix: cart spec

* chore: expand integration test with item level totals

* feat: add a few more test cases

---------

Co-authored-by: Oli Juhl <59018053+olivermrbl@users.noreply.github.com>

packages/modules/promotion/src/utils/compute-actions/line-items.ts

@@ -164,6 +164,7 @@ function applyPromotionToItems(
         item_id: item.id,
         amount,
         code: promotion.code!,
+        is_tax_inclusive: promotion.is_tax_inclusive,
       })
     } else if (isTargetShippingMethod) {
       computedActions.push({