feat(dashboard,js-sdk,medusa): add ability to add outbound items to claim (#8502)

what:

- user can add/remove/update outbound items to a claim
- adds API to query variants

Note: There are several paths that are not implemented yet correctly, but have some code lying around. Those will be tackled in the followup PRs

https://github.com/user-attachments/assets/cadb3f7a-982f-44c7-8d7e-9f4f26949f4f

RESOLVES CC-330
RESOLVES CC-296

packages/medusa/src/api/middlewares.ts

@@ -21,6 +21,7 @@ import { adminPricePreferencesRoutesMiddlewares } from "./admin/price-preference
 import { adminProductCategoryRoutesMiddlewares } from "./admin/product-categories/middlewares"
 import { adminProductTagRoutesMiddlewares } from "./admin/product-tags/middlewares"
 import { adminProductTypeRoutesMiddlewares } from "./admin/product-types/middlewares"
+import { adminProductVariantRoutesMiddlewares } from "./admin/product-variants/middlewares"
 import { adminProductRoutesMiddlewares } from "./admin/products/middlewares"
 import { adminPromotionRoutesMiddlewares } from "./admin/promotions/middlewares"
 import { adminRefundReasonsRoutesMiddlewares } from "./admin/refund-reasons/middlewares"
@@ -110,4 +111,5 @@ export default defineMiddlewares([
   ...adminClaimRoutesMiddlewares,
   ...adminRefundReasonsRoutesMiddlewares,
   ...adminExchangeRoutesMiddlewares,
+  ...adminProductVariantRoutesMiddlewares,
 ])