fix(comp:input): sync design and update css variable

[danranVm]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines
• Tests for the changes have been added/updated or not needed
• Docs and demo have been added/updated or not needed

What is the current behavior?

• 样式同步最新设计规范
• 把所有 input 的 css 变量抽到了 form 里，为后续统一css 变量做准备。

What is the new behavior?

Other information

[idux-bot]

This preview will be available after the AzureCI is passed.

[codecov]

Codecov Report

Merging #1602 (b4db02f) into main (f68df61) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head b4db02f differs from pull request most recent head 9e9b26e. Consider uploading reports for the commit 9e9b26e to get more accurate results

@@           Coverage Diff           @@
##             main    #1602   +/-   ##
=======================================
  Coverage   92.56%   92.56%           
=======================================
  Files         338      338           
  Lines       31541    31542    +1     
  Branches     3602     3602           
=======================================
+ Hits        29197    29198    +1     
  Misses       2344     2344           

Impacted Files	Coverage Δ
packages/components/input/src/Input.tsx	100.00% <100.00%> (ø)