Implement basic texture upload. This change modifies ImageHelper's methods to upload textures to fix webgpu API calls, as well as fully implements uploading texture data via TextureWgpu::setImage for RGBA8 formats. Bug: angleproject:8457 Change-Id: I1c5be3d79ad996a709086ca7157cca6229a336ce Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5398002 Reviewed-by: Matthew Denton <mpdenton@chromium.org> Commit-Queue: Liza Burakova <liza@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>