Add ElementReference to InputRadio

[campersau]

Description

Add Element property to InputRadio just like the input fields in #29555
Since InputRadioGroup does not use an actual DOM element I left it out.

aspnetcore/src/Components/Web/src/Forms/InputRadioGroup.cs

Lines 53 to 63 in 82e6b60

	protected override void BuildRenderTree(RenderTreeBuilder builder)
	{
	Debug.Assert(_context != null);
	// Note that we must not set IsFixed=true on the CascadingValue, because the mutations to _context
	// are what cause the descendant InputRadio components to re-render themselves
	builder.OpenComponent<CascadingValue<InputRadioContext>>(0);
	builder.AddAttribute(2, "Value", _context);
	builder.AddAttribute(3, "ChildContent", ChildContent);
	builder.CloseComponent();
	}

Fixes #40804

[MackinnonBuck]

Looks great.

I believe the reason we didn't initially support this was because radio buttons were always being re-rendered, causing element references to frequently become invalidated, making them useless (#31610). However, since that was fixed in #40148, it should be safe to accept this change.

Thanks @campersau!