AtSwitch组建调整关闭 背景颜色

### Taro UI 版本信息

v2.3.4

### 问题描述

无法改变AtButton关闭状态下的背景颜色

### 复现步骤

添加background backgroundColor都无效

### 复现代码

### 报错信息

无

### 系统信息

Taro CLI 3.3.9 environment info:
System:
OS: macOS 11.2.2
Shell: 3.2.57 - /bin/bash
Binaries:
Node: 14.17.6 - /usr/local/bin/node
Yarn: 1.22.11 - /usr/local/bin/yarn
npm: 6.14.15 - /usr/local/bin/npm
npmPackages:
@tarojs/components: 3.3.9 => 3.3.9
@tarojs/mini-runner: 3.3.9 => 3.3.9
@tarojs/react: 3.3.9 => 3.3.9
@tarojs/runtime: 3.3.9 => 3.3.9
@tarojs/taro: 3.3.9 => 3.3.9
@tarojs/webpack-runner: 3.3.9 => 3.3.9
babel-preset-taro: 3.3.9 => 3.3.9
eslint-config-taro: 3.3.9 => 3.3.9
react: ^17.0.0 => 17.0.2
taro-ui: ^3.0.0-alpha => 3.0.0-alpha.3

### 补充信息