🐛 图标图层自定义图标映射，更新字段不及时生效

### 🐛 图标图层自定义图标映射，更新字段不及时生效

切换字段后图层更新不及时，需要刷新后才生效，L7 不支持 domain 更新

https://riddle.alibaba-inc.com/riddles/f7fada99

### 📷 Step to reproduce

### 🏞 Expected result

L7 支持 domain 更新

https://github.com/antvis/L7/issues/2086

Start by inspecting the icon-layer custom icon mapping and the field-switch update flow. Read the linked L7 issue #2086 for the domain-update limitation, then reproduce the problem by changing the field and checking whether the layer updates without a refresh. Done means the selected field and icon mapping take effect immediately.

Written by the indexing model from the issue text.