feat: 通话中禁用回拨功能

src/features/invigilation/RealtimeMonitoring/RealtimeMonitoringFull.vue

@@ -306,6 +306,9 @@ export default {
 
     /** 回拨 */
     onBackCall(data) {
+      if (this.talking.examRecordId) {
+        return;
+      }
       this.operationStudent["back-call"] = data;
       this.operationStudent["talk"] = data;
       this.toTalk();