fix: input 光标设置错误

[oasis-cloud]

这个 PR 做了什么? (简要描述所做更改)

<Input style={{background: '#f0f0f0'}}  defaultValue={8888888888} cursor={0} />
<Input style={{background: '#f0f0f0'}}  defaultValue={8888888888} cursor={2} />

在上面的 demo 中，cursor 无法正确设置。除此外，当进行非文本末尾的删除操作后，光标会跳回最后一位。

这个 PR 是什么类型? (至少选择一个)

• 错误修复(Bugfix) issue: fix #

这个 PR 涉及以下平台:

• 所有小程序

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 57.86%. Comparing base (8256f13) to head (b0ebb8c).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #17476   +/-   ##
=======================================
  Coverage   57.86%   57.86%           
=======================================
  Files         468      468           
  Lines       26458    26458           
  Branches     5812     5829   +17     
=======================================
  Hits        15309    15309           
+ Misses       9665     9573   -92     
- Partials     1484     1576   +92     

Flag	Coverage Δ
taro-cli	72.37% <ø> (ø)
taro-runtime	59.87% <ø> (ø)
taro-web	49.68% <ø> (ø)

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see 28 files with indirect coverage changes

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[qhanw]

该问题不仅仅是删除时会出现，在输入框非文本末尾位置添加内空时，在真机上光标也会跳回最后一位，不知道是不是相同问题。

[fkc-alt]

请问修复好了吗