[Blazor] Generate marker key doesn't work for strings.

[javiercn]

aspnetcore/src/Components/Endpoints/src/Rendering/SSRRenderModeBoundary.cs

Lines 209 to 222 in 223fe49

	private ComponentMarkerKey GenerateMarkerKey(int sequence, object? componentKey)
	{
	var componentTypeNameHash = _componentTypeNameHashCache.GetOrAdd(_componentType, TypeNameHash.Compute);
	var sequenceString = sequence.ToString(CultureInfo.InvariantCulture);
	var locationHash = $"{componentTypeNameHash}:{sequenceString}";
	var formattedComponentKey = (componentKey as IFormattable)?.ToString(null, CultureInfo.InvariantCulture) ?? string.Empty;
	return new()
	{
	LocationHash = locationHash,
	FormattedComponentKey = formattedComponentKey,
	};
	}

The attached code fails when you provide a string as a key, since strings are not IFormattable. We should explicitly check if the key is already a string and use it directly.

We should also have a reasonable set of tests that validate that all common primitive types that we expect to work (ints, guids, and so on) successfully generate a key string.