style: 优化带教次数显示默认值

src/views/components/roleInfo/roleInfoPanel.vue

@@ -184,7 +184,7 @@
                       type="text"
                       style="cursor: pointer;z-index:10;"
                       @click.stop="openMentorRecordDrawer(items)"
-                    >{{ items.teach_num || '-' }}次</el-button>  
+                    >{{ items.teach_num || 0 }}次</el-button>  
                   </div>
                 </div>
               </div>