fix: SelectedOptionChanged called twice in FluentCombobox

[nwoolls]

🐛 Bug Report

I am trying to handle scenarios where a user clears the value in a FluentCombobox, or types a value that is not in the list. I am using SelectedOptionChanged to do so. However, SelectedOptionChanged is called twice, once with a parameter of null and then again with the previously selected item, even though the rendered combo box does not have the previously selected item in it.

💻 Repro or Code Sample

dotnet new fluentblazor

@rendermode InteractiveServer

<FluentCombobox Items="_items"
                TOption="string"
                SelectedOptionChanged="x => HandleOriginProductChanged(x)"/>

@code {
    private List<string> _items = [ "Item 1", "Item 2", "Item 3" ];

    private void HandleOriginProductChanged(string? value)
    {
        Console.WriteLine($"Selected product: {value}");
    }
}

1. Run the above sample
2. Select "Item 1" from the combo
3. Select "Item 2" from the combo
4. Clear out the selected value (or type a value that does not exist in the list)

🤔 Expected Behavior

Console log:

Selected product: Item 1
Selected product: Item 2
Selected product: 

😯 Current Behavior

Console log:

Selected product: Item 1
Selected product: Item 2
Selected product: 
Selected product: Item 2

💁 Possible Solution

N/A - I may be willing to work on a fix time permitting.

🔦 Context

FWIW I saw a similar issue here that was fixed in 4.7.2, but I am still seeing the problem reported above:

• FluentSelect's SelectedOptionChanged triggered twice with different values #1965

🌍 Your Environment

• OS & Device: MacOS
• Browser: Google Chrome, Apple Safari
• .NET and Fluent UI Blazor library Version: 8.0.5 and 4.7.2

[vnbaaij]

We are in the middle of changing the list components to inherit from InputBase (instead of ComponentBase). We will take this in as part of that work.

[vnbaaij]

Can confirm that this will be fixed with PR #2118