feat(core-flows, medusa): add shipping methods to cart API (#7150)

* feat(core-flows, medusa): add shipping methods to cart API

* chore: change id to option_id

* chore: use list listShippingOptionsForContext instead of validateShippingOption

* chore: remove comment

* chore: add refresh shipping methods step

* chore: set cart step

* chore: update all workflows to refresh shipping methods

* chore: add tests + cleanup

.changeset/thick-bats-rescue.md

@@ -0,0 +1,6 @@
+---
+"@medusajs/core-flows": patch
+"@medusajs/medusa": patch
+---
+
+feat(core-flows, medusa): add shipping methods to cart API