Since Ozone supports external target only
for images created with EGL_EXT_image_dma_buf_import

Started failing when Texture3D was enabled in
https://chromium-review.googlesource.com/c/angle/angle/+/1682782

Bug: angleproject:3188
Change-Id: I4131b51f16907d12088869b7ee02799ab1b39fec
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1687980Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Yuly Novikov <ynovikov@chromium.org>