fix(x-web): 正确处理未设置 modelValue和 value 的情况

[Otto-J]

相关自动化测试，涉及 input/textarea 两个组件

https://gitcode.net/dcloud/hello-uni-app-x/-/commit/de40580cee832b261aee167210196f4e4caa1ae3

[github-actions]

Size report

Path	Size
packages/size-check/dist/size-check.es.js	45.66 KB (0%)
packages/size-check/dist/style.css	2.89 KB (0%)
packages/uni-app/dist/uni-app.es.js	2.05 KB (0%)
packages/uni-h5-vue/dist/vue.runtime.esm.js	76.23 KB (0%)
packages/uni-mp-vue/dist/vue.runtime.esm.js	58.89 KB (0%)
packages/uni-mp-alipay/dist/uni.api.esm.js	12.91 KB (0%)
packages/uni-mp-alipay/dist/uni.mp.esm.js	7.57 KB (0%)
packages/uni-mp-baidu/dist/uni.api.esm.js	9.93 KB (0%)
packages/uni-mp-baidu/dist/uni.mp.esm.js	9.27 KB (0%)
packages/uni-mp-qq/dist/uni.api.esm.js	9.22 KB (0%)
packages/uni-mp-qq/dist/uni.mp.esm.js	7.22 KB (0%)
packages/uni-mp-toutiao/dist/uni.api.esm.js	9.37 KB (0%)
packages/uni-mp-toutiao/dist/uni.mp.esm.js	9.09 KB (0%)
packages/uni-mp-weixin/dist/uni.api.esm.js	10.04 KB (0%)
packages/uni-mp-weixin/dist/uni.mp.esm.js	7.34 KB (0%)
packages/uni-quickapp-webview/dist/uni.api.esm.js	9.18 KB (0%)
packages/uni-quickapp-webview/dist/uni.mp.esm.js	8.42 KB (0%)