[WebGPU] Document Chrome 133 supported for undefined value for unknown limits

[chrisdavidmills]

See https://developer.chrome.com/blog/new-in-webgpu-133#allow_unknown_limits_to_be_requested_with_undefined_value for details

• Add information to https://developer.mozilla.org/en-US/docs/Web/API/GPUSupportedLimits.
• And probably https://developer.mozilla.org/en-US/docs/Web/API/GPUAdapter/requestDevice as well.
• Add BCD probably just for the first one.