refactor: id list에서 set으로 변경

Author: GaBaljaintheroom

app/domain/subscription-domain/src/main/java/org/example/usecase/ArtistSubscriptionUseCase.java

@@ -55,7 +55,7 @@ public void artistSubscribe(ArtistSubscriptionMessageDomainRequest request) {
     public void artistUnsubscribe(ArtistSubscriptionMessageDomainRequest request) {
         var artistIds = request.artists().stream()
             .map(ArtistMessageDomainRequest::artistId)
-            .toList();
+            .collect(Collectors.toSet());
 
         var artistSubscriptions = artistSubscriptionRepository.findSubscriptionList(
             request.userFcmToken());

app/domain/subscription-domain/src/main/java/org/example/usecase/GenreSubscriptionUseCase.java

@@ -55,7 +55,7 @@ public void genreSubscribe(GenreSubscriptionMessageDomainRequest request) {
     public void genreUnsubscribe(GenreSubscriptionMessageDomainRequest request) {
         var genreIds = request.genres().stream()
             .map(GenreMessageDomainRequest::genreId)
-            .toList();
+            .collect(Collectors.toSet());
 
         var artistSubscriptions = genreSubscriptionRepository.findSubscriptionList(
             request.userFcmToken());