fix: 카카오톡 bulk send 오류 fix

mens-core/src/main/java/kr/xit/core/spring/util/ApiWebClientUtil.java

@@ -131,10 +131,9 @@ public class ApiWebClientUtil {
 
         // FIXME: Kkotalk 값 설정
         Map<String, String> map = new HashMap<>();
-        map.put(Constants.JwtToken.PARTNER_REST_API_KEY.getCode(),
-            String.format("KakaoAK %s", ensDTO.getKakaoPartnerRestApiKey()));
-        map.put(HttpHeaders.AUTHORIZATION,
-            String.format("KakaoAK %s", ensDTO.getKakaoDealerRestApiKey()));
+        map.put(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_VALUE);
+        map.put(HttpHeaders.AUTHORIZATION, String.format("KakaoAK %s", ensDTO.getKakaoDealerRestApiKey()));
+        map.put(Constants.JwtToken.PARTNER_REST_API_KEY.getCode(), String.format("KakaoAK %s", ensDTO.getKakaoPartnerRestApiKey()));
         map.put(Constants.JwtToken.SETTLE_ID.getCode(), ensDTO.getKakaoSettleId());
 
         return exchange(url, method, body, rtnClzz, map);