feat(Dropdown): add OnClick event callback

[ArgoZhang]

add OnClick event callback

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 #5321

Regression?

• Yes
• No

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

[是否影响老版本]

Risk

• High
• Medium
• Low

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Verification

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• Automated

Packaging changes reviewed?

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• 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 OnClick and OnClickWithoutRender events to the Dropdown component.

New Features:

• Added an OnClick event callback to the Dropdown component to allow custom logic to be executed when the dropdown button is clicked.
• Added an OnClickWithoutRender event callback to the Dropdown component. This event is useful for scenarios where re-rendering the parent component is not desired after the click action.

[sourcery-ai]

Reviewer's Guide by Sourcery

This PR adds support for OnClick event callbacks in the Dropdown component. It introduces new parameters and associated event handling logic in the component, updates the markup to integrate these changes, and modifies sample usage and documentation to reflect the new functionality.

Sequence diagram for Dropdown OnClick event callback

sequenceDiagram
    actor User
    participant Dropdown

    note over Dropdown: On button click triggers OnClickButton()
    User->>Dropdown: Clicks on dropdown button

    Dropdown->>Dropdown: if (OnClickWithoutRender != null)
    alt OnClickWithoutRender exists
        Dropdown->>Dropdown: await OnClickWithoutRender()
    end
    Dropdown->>Dropdown: if (OnClick.HasDelegate)
    alt OnClick delegate present
        Dropdown->>Dropdown: await OnClick.InvokeAsync()
    end

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File-Level Changes

Change	Details	Files
Introduced OnClick and OnClickWithoutRender event parameters in the Dropdown component.	Added new parameters to accept OnClick (EventCallback) and OnClickWithoutRender (Func) in the component's C# code. Implemented a new private method OnClickButton to handle click events by invoking the provided callbacks conditionally.	src/BootstrapBlazor/Components/Dropdown/Dropdown.razor.cs
Updated component markup to integrate the new click event handling functionality.	Replaced a static button with a DynamicElement in the Dropdown.razor to bind the OnClickButton event handler. Configured DynamicElement with TriggerClick and OnClick attributes to support the new event callback.	src/BootstrapBlazor/Components/Dropdown/Dropdown.razor
Enhanced sample code and documentation to demonstrate the usage of the new event callbacks.	Updated sample events list in Dropdowns.razor.cs to include OnClick and OnClickWithoutRender event descriptions. Modified sample usage in Dropdowns.razor to trigger the new event functionalities by adjusting ShowSplit usage. Revised locale files (en-US and zh-CN) to support event description entries.	src/BootstrapBlazor.Server/Components/Samples/Dropdowns.razor.cs src/BootstrapBlazor.Server/Components/Samples/Dropdowns.razor src/BootstrapBlazor.Server/Locales/en-US.json src/BootstrapBlazor.Server/Locales/zh-CN.json

Assessment against linked issues

Issue	Objective	Addressed	Explanation
#5303	Enable developers to add @OnClick to the first button when ShowSplit='true'	✅
#5303	Provide separate click events for split dropdown buttons similar to GitHub's Copilot component	✅

Possibly linked issues

• feat(Dropdown): when ShowSplit="true", expose first(left) button click event and IsAsync attribute of it. #5303: The PR implements the feature request described in the issue by adding an OnClick event callback to the dropdown component.
• feat(Dropdown): when ShowSplit="true", expose first(left) button click event and IsAsync attribute of it. #5303: The PR fixes issue feat(Dropdown): when ShowSplit="true", expose first(left) button click event and IsAsync attribute of it. #5303 by adding an OnClick event callback to Dropdown component, addressing the unexpected behavior of OnSelectedItemChanged.

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[sourcery-ai]

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

Overall Comments:

• Consider forwarding the MouseEventArgs parameter to OnClick.InvokeAsync so that event handlers can access click details.
• Review if invoking both OnClickWithoutRender and OnClick in sequence is intended and document the order if necessary.

Here's what I looked at during the review

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

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[sourcery-ai]

issue: Event callback handler signature may be missing MouseEventArgs parameter.

Since the OnClick parameter is of type EventCallback, consider updating OnClickButton to accept a MouseEventArgs parameter (e.g. OnClickButton(MouseEventArgs e)) and passing it to OnClick.InvokeAsync(e). This ensures that any event data provided by the underlying click event is not lost.