feat(Cascader): add OnBlurAsync parameter

[ArgoZhang]

add OnBlurAsync parameter

Summary of the changes (Less than 80 chars)

简单描述你更改了什么, 不超过80个字符；如果有关联 Issue 请在下方填写相关编号

Description

fixes #4598

Regression?

• Yes
• No

[If yes, specify the version the behavior has regressed from]

[是否影响老版本]

Risk

• High
• Medium
• Low

[Justify the selection above]

Verification

• Manual (required)
• Automated

Packaging changes reviewed?

• Yes
• No
• N/A

☑️ 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
• Merge the latest code from the main branch

Summary by Sourcery

Add the OnBlurAsync parameter to the Cascader component to support asynchronous operations on blur events and include a corresponding unit test to ensure its functionality.

New Features:

• Introduce the OnBlurAsync parameter to the Cascader component, allowing asynchronous operations to be triggered when the component loses focus.

Tests:

• Add a unit test to verify the functionality of the OnBlurAsync parameter in the Cascader component.

[sourcery-ai]

Reviewer's Guide by Sourcery

This PR adds a new OnBlurAsync parameter to the Cascader component, allowing users to handle blur events asynchronously. The implementation includes adding the parameter property, implementing the blur event handler, and adding unit tests to verify the functionality.

Sequence diagram for OnBlurAsync event handling

sequenceDiagram
    participant User
    participant Cascader
    participant OnBlurAsyncHandler
    User->>Cascader: Blur input
    Cascader->>Cascader: OnBlur()
    Cascader->>OnBlurAsyncHandler: OnBlurAsync(Value)
    OnBlurAsyncHandler-->>Cascader: Task Completed
    Cascader-->>User: Blur event handled

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File-Level Changes

Change	Details	Files
Added new OnBlurAsync parameter and handler to Cascader component	Added OnBlurAsync parameter property of type Func<TValue, Task> Implemented OnBlur event handler method to invoke OnBlurAsync callback Added @OnBlur event binding to the input element	src/BootstrapBlazor/Components/Cascader/Cascader.razor.cs src/BootstrapBlazor/Components/Cascader/Cascader.razor
Added unit test for OnBlurAsync functionality	Created test case to verify OnBlurAsync callback is triggered Verified correct value is passed to the callback	test/UnitTest/Components/CascaderTest.cs
Minor markup improvements	Changed self-closing BootstrapLabel tag to explicit closing tag	src/BootstrapBlazor/Components/Cascader/Cascader.razor

Assessment against linked issues

Issue	Objective	Addressed	Explanation
#4598	Add OnBlurAsync parameter to the Cascader component	✅

Possibly linked issues

• feat(Cascader): add OnBlurAsync parameter #4598: The PR implements the OnBlurAsync parameter as requested in the issue.

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[sourcery-ai]

Hey @ArgoZhang - I've reviewed your changes - here's some feedback:

Overall Comments:

• Please enhance the PR description to explain the motivation and use cases for adding the OnBlurAsync parameter. This will help with future maintenance.

Here's what I looked at during the review

• 🟢 General issues: all looks good
• 🟢 Security: all looks good
• 🟡 Testing: 1 issue found
• 🟢 Complexity: all looks good
• 🟢 Documentation: all looks good

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (36feb53) to head (b64cef9).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #4599   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          620       620           
  Lines        27383     27390    +7     
  Branches      3919      3920    +1     
=========================================
+ Hits         27383     27390    +7     

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