update Blazor to .NET 8

[ElderJames]

🤔 This is a ...

• New feature
• Bug fix
• Site / documentation update
• Demo update
• Component style update
• Bundle size optimization
• Performance optimization
• Refactoring
• Code style optimization
• Test Case
• Branch merge
• Other (about what?)

🔗 Related issue link

💡 Background and solution

📝 Changelog

Language	Changelog
🇺🇸 English
🇨🇳 Chinese

☑️ Self Check before Merge

⚠️ Please check all items below before review. ⚠️

• Doc is updated/provided or not needed
• Demo is updated/provided or not needed
• Changelog is provided or not needed

[github-actions]

[codecov]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (2b53e61) 1.55% compared to head (5d55935) 44.72%.
Report is 1 commits behind head on master.

Files	Patch %	Lines
components/select/Select.razor.cs	20.00%	3 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #3514       +/-   ##
===========================================
+ Coverage    1.55%   44.72%   +43.17%     
===========================================
  Files         566      566               
  Lines       26899    26961       +62     
  Branches     5566     5587       +21     
===========================================
+ Hits          417    12059    +11642     
+ Misses      26442    13926    -12516     
- Partials       40      976      +936     

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