新活检：失败，关闭摄像头

src/features/OnlineExam/Examing/FaceMotion/FaceMotion.vue

@@ -349,6 +349,7 @@ export default {
       this.faceBiopsyInfo = faceBiopsyInfo;
     },
     async closeMe() {
+      this.closeCamera();
       this.updateIsDoingFaceLiveness(false);
       const faceLiveResultData = await this.$httpPostRetry(
         "/api/ecs_oe_student/faceBiopsy/saveFaceBiopsyResult",
@@ -1056,7 +1057,7 @@ export default {
     closeCamera: function() {
       console.log("关闭摄像头");
       const video = document.getElementById("inputVideo");
-      if (video.srcObject) {
+      if (video && video.srcObject) {
         video.srcObject.getTracks().forEach(function(track) {
           track.stop();
         });