Limit multiple platform manifests to one for size check

client.Pull will only pull one matching platform by default.
When checking the size of image we match that behavior so that
we don't look for multiple platforms that might not exist on disk.

Signed-off-by: Darren Shepherd <darren@rancher.com>

images/image.go

@@ -119,7 +119,7 @@ func (image *Image) Size(ctx context.Context, provider content.Provider, platfor
 		}
 		size += desc.Size
 		return nil, nil
-	}), FilterPlatforms(ChildrenHandler(provider), platform)), image.Target)
+	}), LimitManifests(FilterPlatforms(ChildrenHandler(provider), platform), platform, 1)), image.Target)
 }
 
 type platformManifest struct {