feat: seperate single and multi choice questions

src/modules/submissions/helpers/check-answer-correctness.helper.ts

@@ -28,7 +28,7 @@ export const checkAnswerCorrectness = (
     }
   }
 
-  if (question.type === QuestionType.MULTI_CHOICE) {
+  if (question.type === QuestionType.SINGLE_CHOICE) {
     if (choiceId === undefined || choiceId === null) {
       throw new BadRequestException('submissions.errors.emptyChoiceId');
     }

src/modules/submissions/helpers/get-next-transition.helper.ts

@@ -18,7 +18,7 @@ export const getNextTransition = (
   );
 
   if (
-    question.type === QuestionType.MULTI_CHOICE &&
+    question.type === QuestionType.SINGLE_CHOICE &&
     answerSubmissionDto.choiceId !== undefined
   ) {
     const transition = transitions.find(