fix: 시큐리티 유틸이 멤버 ID 파싱에 실패할 경우 커스텀 예외 던지도록 수정

src/main/java/com/depromeet/global/util/SecurityUtil.java

@@ -1,5 +1,7 @@
 package com.depromeet.global.util;
 
+import com.depromeet.global.error.exception.CustomException;
+import com.depromeet.global.error.exception.ErrorCode;
 import org.springframework.security.core.Authentication;
 import org.springframework.security.core.context.SecurityContextHolder;
 import org.springframework.stereotype.Component;
@@ -9,6 +11,10 @@ public class SecurityUtil {
 
     public Long getCurrentMemberId() {
         Authentication authentication = SecurityContextHolder.getContext().getAuthentication();
-        return Long.parseLong(authentication.getName());
+        try {
+            return Long.parseLong(authentication.getName());
+        } catch (Exception e) {
+            throw new CustomException(ErrorCode.AUTH_NOT_FOUND);
+        }
     }
 }