fix(steps): Add flex on steps to fix ie11

[AdrianoRuberto]

🤔 This is a ...

• New feature
• Bug fix
• Site / document update
• Component style update
• TypeScript definition update
• Refactoring
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🔗 Related issue link

#23453

💡 Background and solution

The problem is the flex default value on ie11 isn't the same as on chrome/ff. Setting flex: 1 0 auto; Make the Steps being displayed correctly.

📝 Changelog

Language	Changelog
🇺🇸 English	-
🇨🇳 Chinese	-

☑️ Self Check before Merge

⚠️ Please check all items below before review. ⚠️

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[afc163]

https://www.codefactor.io/repository/github/ant-design/ant-design/pull/23561

[ant-design-bot]

[afc163]

Could you help to update changelog here?

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[codecov]

Codecov Report

Merging #23561 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master   #23561   +/-   ##
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  Coverage   98.50%   98.50%           
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  Files         363      363           
  Lines        7267     7267           
  Branches     2002     1953   -49     
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  Hits         7158     7158           
  Misses        109      109           

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[afc163]

Why closing?

[AdrianoRuberto]

This isn't working like it's supposed to

[AdrianoRuberto]

I thought adding flex: 1 0 auto at .steps-vertical would fix the problem, but it isn't the case.
I think I need to add it on ant-step-item instead but I need more time testing