Vulkan: Check source image usage flags in copy paths ... instead of the format feature flags. If the source of the copy is has external format (allowed with glCopy[Sub]TextureCHROMIUM), the format feature checks are unable to query the format features. However, the image usage flags already have the required information (whether the image can be copied from, sampled from, etc). Bug: chromium:383056998 Change-Id: I2ba8820751eb526ef497a8be724193276fd46160 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6238265 Commit-Queue: Amirali Abdolrashidi <abdolrashidi@google.com> Reviewed-by: Charlie Lao <cclao@google.com> Auto-Submit: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Amirali Abdolrashidi <abdolrashidi@google.com>