fix(user) : UserRepository import추가

fix(user) : UserRepository import추가

Author: Hyeseung-OH

backend/src/main/java/com/backend/domain/user/service/EmailService.java

@@ -1,6 +1,10 @@
 package com.backend.domain.user.service;
 
+import com.backend.domain.user.repository.UserRepository;
+
 import com.backend.domain.user.util.RedisUtil;
+import com.backend.global.exception.BusinessException;
+import com.backend.global.exception.ErrorCode;
 import jakarta.mail.MessagingException;
 import jakarta.mail.internet.MimeMessage;
 import lombok.RequiredArgsConstructor;