feat: 鸿蒙配置添加是否支持css变量解析开关

[heiazu]

这个 PR 做了什么? (简要描述所做更改)

为harmony下添加cssVariables选项配置，用于控制是否自动载入变量解析插件

这个 PR 是什么类型? (至少选择一个)

• 错误修复(Bugfix) issue: fix #
• 新功能(Feature)
• 代码重构(Refactor)
• TypeScript 类型定义修改(Typings)
• 文档修改(Docs)
• 代码风格更新(Code style update)
• 其他，请描述(Other, please describe):

这个 PR 涉及以下平台:

• 所有小程序
• 微信小程序
• 支付宝小程序
• 百度小程序
• 字节跳动小程序
• QQ 轻应用
• 京东小程序
• 快应用平台（QuickApp）
• Web 平台（H5）
• 移动端（React-Native）
• 鸿蒙（harmony）

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 58.52%. Comparing base (f1a5b48) to head (91526e9).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #17381   +/-   ##
=======================================
  Coverage   58.52%   58.52%           
=======================================
  Files         468      468           
  Lines       27136    27136           
  Branches     5917     5936   +19     
=======================================
  Hits        15882    15882           
+ Misses       9877     9782   -95     
- Partials     1377     1472   +95     

Flag	Coverage Δ
taro-cli	72.37% <ø> (ø)
taro-runtime	59.87% <ø> (ø)
taro-web	52.77% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

see 23 files with indirect coverage changes