fix: `docker pull` with platform checks wrong image tag

This fixes a bug where, if a user pulls an image with a tag != `latest` and
a specific platform, we return an NotFound error for the wrong (`latest`) tag.
see: https://github.com/moby/moby/issues/45558

This bug was introduced in https://github.com/moby/moby/commit/779a5b3029473c6bb61c2d08a43e0a8d68a73d7f
in the changes to `daemon/images/image_pull.go`, when we started returning the error from the call to
`GetImage` after the pull. We do this call, if pulling with a specified platform, to check if the platform
of the pulled image matches the requested platform (for cases with single-arch images).
However, when we call `GetImage` we're not passing the image tag, only name, so `GetImage` assumes `latest`
which breaks when the user has requested a different tag, since there might not be such an image in the store.

Signed-off-by: Laura Brehm <laurabrehm@hey.com>

daemon/images/image_pull.go

@@ -63,7 +63,7 @@ func (i *ImageService) PullImage(ctx context.Context, image, tag string, platfor
 		// we allow the image to have a non-matching architecture. The code
 		// below checks for this situation, and returns a warning to the client,
 		// as well as logging it to the daemon logs.
-		img, err := i.GetImage(ctx, image, imagetypes.GetImageOpts{Platform: platform})
+		img, err := i.GetImage(ctx, ref.String(), imagetypes.GetImageOpts{Platform: platform})
 
 		// Note that this is a special case where GetImage returns both an image
 		// and an error: https://github.com/docker/docker/blob/v20.10.7/daemon/images/image.go#L175-L183