cli/registry: fix client.pullManifestList not de-referencing manifest

Kudos to gosec;

    cli/registry/client/fetcher.go:205:57: G601: Implicit memory aliasing in for loop. (gosec)
            imageManifest.Descriptor.Platform = types.OCIPlatform(&manifestDescriptor.Platform)
                                                                  ^

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit 5250f1b)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cli/registry/client/fetcher.go

@@ -202,7 +202,8 @@ func pullManifestList(ctx context.Context, ref reference.Named, repo distributio
 		}
 
 		// Replace platform from config
-		imageManifest.Descriptor.Platform = types.OCIPlatform(&manifestDescriptor.Platform)
+		p := manifestDescriptor.Platform
+		imageManifest.Descriptor.Platform = types.OCIPlatform(&p)
 
 		infos = append(infos, imageManifest)
 	}