Describe the bug

If HTML attribute is added dynamically, you can’t check for addition using existing methods like ShouldBeAddition or ShouldBeAttributeChange.

Example:
https://stackoverflow.com/questions/75345362/bunit-check-for-attribute-addition

Expected behavior:

I want something like ShouldBeAttributeAddition

Version info:

• bUnit version: latest
• .NET Runtime and Blazor version: latest
• OS type and version: Win10, latest