Merge pull request #217 from DevKor-github/feat/keep-nickname

feat: 회원 탈퇴 시 닉네임 보존

Author: soonduck-dreams

src/main/java/org/devkor/apu/saerok_server/domain/user/core/entity/User.java

@@ -48,7 +48,6 @@ public class User extends SoftDeletableAuditable {
     private Short defaultProfileImageVariant;
 
     public void anonymizeForWithdrawal() {
-        this.setNickname(null);
         this.email = null;
         this.phone = null;
         this.gender = null;