cli/trust: GetNotaryRepository: remove uses of RepositoryInfo.Class

The Class field was added because  Docker Hub registry required a special
scope to be set for pulling plugins;

    HTTP/1.1 401 Unauthorized
    ...
    Www-Authenticate: Bearer realm="https://auth.docker.io/token",service="registry.docker.io",scope="repository(plugin):vieux/sshfs:pull",error="insufficient_scope"

This is no longer a requirement, and the field is no longer set.

updates 0ba820e

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit ed9fcf3)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

cli/trust/trust.go

@@ -157,7 +157,6 @@ func GetNotaryRepository(in io.Reader, out io.Writer, userAgent string, repoInfo
 	scope := auth.RepositoryScope{
 		Repository: repoInfo.Name.Name(),
 		Actions:    actions,
-		Class:      repoInfo.Class, // TODO(thaJeztah): Class is no longer needed for plugins and can likely be removed; see https://github.com/docker/cli/pull/4114#discussion_r1145430825
 	}
 	creds := simpleCredentialStore{auth: *authConfig}
 	tokenHandlerOptions := auth.TokenHandlerOptions{