[Bug][web] fix A bug occurred when other sending methods were switch… (#4385)

Author: javaht

dinky-web/src/pages/RegCenter/Alert/AlertInstance/components/AlertTypeChoose/InstanceForm/WeChat/index.tsx

@@ -86,6 +86,7 @@ const WeChat = (props: WeChatProps) => {
           label={l('rc.ai.sendType')}
           initialValue={sendType ?? 'app'}
           fieldProps={{
+            value: sendType,
             onChange: (e) => setSendType(e.target.value)
           }}
           options={[