fix 多媒体考试的score:0被处理成null

src/features/mark/MultiMediaMarkBody.vue

@@ -152,7 +152,7 @@ watch(
         questionForRender.objective = questionBody.objective;
         questionForRender.standardAnswer = questionBody.answer;
         questionForRender.studentAnswer = stuAns.answer;
-        questionForRender.score = taskQuestion?.score || null;
+        questionForRender.score = taskQuestion?.score ?? null;
         questionForRender.totalScore = taskQuestion?.maxScore || 0;
         questions.push(questionForRender);
       }