fix(medusa, admin-ui): Add deleted_at to Return Reason unique constraint (#4834)

* Update return reason create to upsert

* Create strange-wombats-invite.md

* Revert upsert, make value index only apply on non-deleted entities

packages/medusa/src/models/return-reason.ts

@@ -14,7 +14,7 @@ import { generateEntityId } from "../utils/generate-entity-id"
 
 @Entity()
 export class ReturnReason extends SoftDeletableEntity {
-  @Index({ unique: true })
+  @Index({ unique: true, where: "deleted_at IS NULL" })
   @Column()
   value: string