修复bug:banner展示选择是，是必填的，未做必填校验

src/views/modules/news/banner-add-or-update.vue

@@ -24,13 +24,11 @@
                   placeholder="标题"></el-input>
       </el-form-item>
       <el-form-item label="所属机构">
-        <el-cascader
-                v-model="dataForm.allDeptIdsShow"
+        <el-cascader v-model="dataForm.allDeptIdsShow"
                      :options="options"
                      :props="{ multiple: true }"
                      clearable
-                collapse-tags
-        ></el-cascader>
+                     collapse-tags></el-cascader>
       </el-form-item>
       <!--<el-form-item label="所属街道"
                     prop="streetId">
@@ -77,7 +75,8 @@
           </el-option>
         </el-select>
       </el-form-item>
-      <el-form-item label="banner位置">
+      <el-form-item label="banner位置"
+                    prop="position">
         <el-select v-model="dataForm.position"
                    placeholder="请选择">
           <el-option v-for="item in positionList"
@@ -164,6 +163,9 @@ export default {
         ],
         gridId: [
           { required: true, message: this.$t('validate.required'), trigger: 'blur' }
+        ],
+        position: [
+          { required: true, message: this.$t('validate.required'), trigger: 'blur' }
         ]
       }
     }