fix: uni-data-picker v-model 无效问题，本地数据为空数据加载时间过长问题

Author: hdx-w

uni_modules/uni-data-picker/components/uni-data-picker/uni-data-picker.vue

@@ -242,11 +242,13 @@
 					value[i] = selected[i].value
 				}
 
+        const item = selected[selected.length - 1]
+
 				if (this.formItem) {
-					const item = selected[selected.length - 1]
 					this.formItem.setValue(item.value)
 				}
 
+        this.$emit('input', item.value)
 				this.$emit('change', {
 					detail: {
 						value: selected

uni_modules/uni-data-picker/components/uni-data-pickerview/uni-data-picker.js

@@ -102,7 +102,7 @@ export default {
   },
   computed: {
     isLocaldata() {
-      return this.localdata.length > 0
+      return (this.localdata && Array.isArray(this.localdata))
     },
     postField() {
 			let fields = [this.field];

uni_modules/uni-data-picker/components/uni-data-pickerview/uni-data-pickerview.vue

@@ -110,7 +110,7 @@
           hasNodes
         } = this._updateBindData()
 
-        if (!this._isTreeView()) {
+        if (!this._isTreeView() && !hasNodes) {
           this.onSelectedChange(node, true)
           return
         }