fix(element): update type of IFormDialog

[Zhhanou]

1. 经检查下面的函数实现，IFormDialog中forConfirm、forCancel的参数middleware的类型IMiddleware泛型应为Form而不是IFormProps
2. 更正对应的文档，并参照antd/FormDialog优化，使文档中的类型定义更清晰。

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[codecov]

Codecov Report

Merging #3360 (fcc9041) into formily_next (867b166) will not change coverage.
The diff coverage is n/a.

@@              Coverage Diff              @@
##           formily_next    #3360   +/-   ##
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  Coverage         96.16%   96.16%           
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  Files               152      152           
  Lines              6573     6573           
  Branches           1835     1835           
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  Hits               6321     6321           
  Misses              223      223           
  Partials             29       29           

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