fix(client): layers now returns manifest - remove duplicate from descriptors

Signed-off-by: Brandt Keller <brandt.keller@defenseunicorns.com>
(cherry picked from commit b07ab77da3)

pkg/registry/client.go

@@ -504,7 +504,6 @@ func (c *Client) Pull(ref string, options ...PullOption) (*PullResult, error) {
 		return nil, err
 	}
 
-	descriptors = append(descriptors, manifest)
 	descriptors = append(descriptors, layers...)
 
 	numDescriptors := len(descriptors)