doc(FormItem): add email validation

[EldarMuhamethanov]

• close [Doc]: Показывается успешная валидация почты, хотя поле заполнено неверно #7358

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Описание

В примере документации в поле ввода почты некорректно работает валидация почты

Изменения

Поправил валидацию почты в примере в документации

[github-actions]

👀 Docs deployed

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• ❌ Storybook

Commit 81e31e6

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.62%. Comparing base (7d400a7) to head (81e31e6).
Report is 2 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #7374   +/-   ##
=======================================
  Coverage   92.62%   92.62%           
=======================================
  Files         374      374           
  Lines       11118    11118           
  Branches     3646     3646           
=======================================
  Hits        10298    10298           
  Misses        820      820           

Flag	Coverage Δ
unittests	92.62% <ø> (ø)

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