chore(user): remove legacy favorites controller and deprecation config

Deletes `FavoriteLegacyController` and its legacy unit/integration tests for
the deprecated `/userinteraction/favorites` contract, and removes the legacy
favorites successor-path configuration from `application.yml`. Also the CHANGELOG.md has been removed accordingly.

Author: polserrano8

CHANGELOG.md

@@ -18,16 +18,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Updated APISIX routes (dev and pro configs) to proxy Favorites requests through /itachallenge/api/v1/user/users/**.
 ### Removed
 - Removed legacy GET endpoint for user solutions from User microservice.
+- Removed deprecated Favorites endpoints from Challenge microservice that pointed to the old User microservice paths.
+- Removed the legacy FavoriteController and related test classes that handled the old Favorites endpoints in the User microservice.
 ### Added
-  - Added new Favorites routes:
-  GET /itachallenge/api/v1/user/users/{userId}/favorites
-  POST /itachallenge/api/v1/user/users/{userId}/favorites/{challengeId}
-  DELETE /itachallenge/api/v1/user/users/{userId}/favorites/{challengeId}
-- Added config properties in application.yml for successor endpoint paths used by legacy deprecation headers.
+- Added new Favorites routes:
+GET /itachallenge/api/v1/user/users/{userId}/favorites
+POST /itachallenge/api/v1/user/users/{userId}/favorites/{challengeId}
+DELETE /itachallenge/api/v1/user/users/{userId}/favorites/{challengeId}
 - Added/updated unit and integration tests to cover both the new Favorites endpoints and the legacy deprecated endpoints.
-### Deprecated
-- Deprecated legacy Favorites routes while keeping them available during a staged rollout.
-- 
+ 
 ### [itachallenge-user-3.2.2-RELEASE] - 2026-02-23
 
 ### Removed

itachallenge-user/src/main/java/com/itachallenge/user/controller/userinteraction/favorite/FavoriteLegacyController.java

@@ -64,10 +64,5 @@ challenge:
   service:
     url: http://apisix-gateway:9080 # IN PRODUCTION
     #url: http://172.17.0.2:8762 # LOCAL IP
-app:
-  api:
-    favorites:
-      successor-version:
-        post-path: "/itachallenge/api/v1/users/{userId}/favorites/{challengeId}"
-        get-path: "/itachallenge/api/v1/users/{userId}/favorites"
-        delete-path: "/itachallenge/api/v1/users/{userId}/favorites/{challengeId}"
+
+