feat(medusa,core-flows,types): adds update promotion rule endpoint + workflow (#6702)

what:

- adds endpoint + workflow to update promotion rule
- adds method in promotion to update promotion rules

.changeset/shaggy-ties-type.md

@@ -0,0 +1,7 @@
+---
+"@medusajs/core-flows": patch
+"@medusajs/medusa": patch
+"@medusajs/types": patch
+---
+
+feat(medusa,core-flows,types): adds update promotion rule endpoint + workflow