fix: 修复选择文件后导致页面滚动的问题

src/platforms/h5/service/api/media/choose-image.js

@@ -9,7 +9,7 @@ let imageInput = null
 const _createInput = function (options) {
   let inputEl = document.createElement('input')
   inputEl.type = 'file'
-  inputEl.style = 'visibility: hidden;z-index: -999;width: 0;height: 0;'
+  inputEl.style = 'position: absolute;visibility: hidden;z-index: -999;width: 0;height: 0;'
   inputEl.accept = 'image/*'
   if (options.count > 1) {
     inputEl.multiple = 'multiple'

src/platforms/h5/service/api/media/choose-video.js

@@ -9,7 +9,7 @@ let videoInput = null
 const _createInput = function (options) {
   let inputEl = document.createElement('input')
   inputEl.type = 'file'
-  inputEl.style = 'visibility: hidden;z-index: -999;width: 0;height: 0;'
+  inputEl.style = 'position: absolute;visibility: hidden;z-index: -999;width: 0;height: 0;'
   inputEl.accept = 'video/*'
   // 经过测试，仅能限制只通过相机拍摄，不能限制只允许从相册选择。
   if (options.sourceType.length === 1 && options.sourceType[0] === 'camera') {