feat(medusa): Add endpoint for retrieving a DiscountCondition (#1525)

packages/medusa-react/mocks/handlers/admin.ts

@@ -1,5 +1,5 @@
-import { fixtures } from "../data"
 import { rest } from "msw"
+import { fixtures } from "../data"
 
 export const adminHandlers = [
   rest.post("/admin/collections/", (req, res, ctx) => {
@@ -784,6 +784,19 @@ export const adminHandlers = [
     )
   }),
 
+  rest.get("/admin/discounts/:id/conditions/:conditionId", (req, res, ctx) => {
+    return res(
+      ctx.status(200),
+      ctx.json({
+        discount_condition: {
+          ...fixtures
+            .get("discount")
+            .rule.conditions.find(c => c.id === req.params.conditionId),
+        },
+      })
+    )
+  }),
+
   rest.delete(
     "/admin/discounts/:id/conditions/:conditionId",
     (req, res, ctx) => {