PC端，话题管理界面，已关闭的话题状态显示已关闭

src/views/modules/group/topic-list.vue

@@ -68,6 +68,7 @@
           <template slot-scope="scope">
             <el-button type="text" size="small" @click="look(scope.row.id)">{{ $t('look') }}</el-button>
             <el-button v-if="scope.row.state !== 20" type="text" size="small" @click="close(scope.row.id)">{{ $t('close') }}</el-button>
+            <el-button type="text" size="small" v-if="scope.row.state ===20" :disabled="true">已关闭</el-button>
           </template>
         </el-table-column>
       </el-table>