[BE] fix: DirectMember Mapper build 누락 directId 추가 (#94)

Author: toychip

src/backend/guild-server/src/main/java/com/asyncgate/guild_server/support/utility/DomainUtil.java

@@ -119,6 +119,7 @@ public static DirectMemberEntity toEntity(final DirectMember directMember) {
         public static DirectMember toDomain(final DirectMemberEntity entity) {
             return DirectMember.builder()
                     .id(entity.getId())
+                    .directId(entity.getDirectId())
                     .memberId(entity.getMemberId())
                     .memberName(entity.getMemberName())
                     .createdDate(entity.getCreatedDate())