Docs: remove twitter image width and height as they are not supported

### What is the documentation issue? https://developer.x.com/en/docs/x-for-websites/cards/overview/markup Twitter image width and height are not supported. Please remove from TwitterImageDescriptor since it create confusion. ### Is there any context that might help us understand? no ### Does the docs page already exist? Please link to it. https://developer.x.com/en/docs/x-for-websites/cards/overview/markup