CLAP-434 Fix: MethodArgumentNotValidException에 대해 400 에러를 반환하도록 수정

Author: joowojr

src/main/java/clap/server/exception/ExceptionAdvice.java

@@ -50,7 +50,7 @@ public ResponseEntity<Object> handleMethodArgumentNotValid(
         return handleExceptionInternalArgs(
                 e,
                 HttpHeaders.EMPTY,
-                GlobalErrorCode.INTERNAL_SERVER_ERROR,
+                GlobalErrorCode.BAD_REQUEST,
                 request,
                 errors
         );