[WebGPU] WGPUTextureFormat_BC2RGBAUnorm and WGPUTextureFormat_BC2RGBAUnormSrgb have the wrong block size in Texture::blockSize
<rdar://problem/117483503>
Pull request: https://github.com/WebKit/WebKit/pull/19551
Committed 269775@main (9444546bdb0b): <https://commits.webkit.org/269775@main> Reviewed commits have been landed. Closing PR #19551 and removing active labels.