NEZ-2635 fix： 创建Metrics的chart时设置Thresholds选择颜色有误

nezha-fronted/src/components/common/rightBox/chart/chartConfig.vue

@@ -484,7 +484,7 @@
           <el-row v-if="chartConfig.param.enable.thresholds && isThresholdConfig(chartConfig.type)">
             <el-form-item
               v-for="(item,index) in chartConfig.param.thresholds"
-              :key="item.color + '' + index"
+              :key="item.id + '' + index"
               class="thresholds-item"
               :prop="'param.thresholds.' + index + '.value'"
               :rules="{ required: true, message: $t('validate.required'), trigger: 'blur'}"
@@ -939,6 +939,7 @@ import publicConfig from '@/components/common/rightBox/chart/publicConfig'
 import chartTypeShow from '@/components/common/rightBox/chart/chartTypeShow'
 import VueTagsInput from '@johmun/vue-tags-input'
 import draggable from 'vuedraggable'
+import { s8 } from '@/components/common/js/common'
 import { randomcolor, ColorReverse } from '@/components/common/js/radomcolor/randomcolor'
 import { isSankey } from '@/components/chart/chart/tools'
 
@@ -1248,6 +1249,7 @@ export default {
     },
     addThresholds () {
       this.chartConfig.param.thresholds.push({
+        id: s8(),
         value: undefined,
         color: randomcolor()
       })