[full-ci] enhancement: use reva client pool selectors (#6452)

* enhancement: use reva client pool selectors

register mock service to registry and pass tests

* enhancement: bump reva

* Fix a couple of linter issues

---------

Co-authored-by: Ralf Haferkamp <rhaferkamp@owncloud.com>

services/proxy/pkg/user/backend/backend.go

@@ -4,9 +4,7 @@ import (
 	"context"
 	"errors"
 
-	gateway "github.com/cs3org/go-cs3apis/cs3/gateway/v1beta1"
 	cs3 "github.com/cs3org/go-cs3apis/cs3/identity/user/v1beta1"
-	"google.golang.org/grpc"
 )
 
 var (
@@ -26,8 +24,3 @@ type UserBackend interface {
 	Authenticate(ctx context.Context, username string, password string) (*cs3.User, string, error)
 	CreateUserFromClaims(ctx context.Context, claims map[string]interface{}) (*cs3.User, error)
 }
-
-// RevaAuthenticator helper interface to mock auth-method from reva gateway-client.
-type RevaAuthenticator interface {
-	Authenticate(ctx context.Context, in *gateway.AuthenticateRequest, opts ...grpc.CallOption) (*gateway.AuthenticateResponse, error)
-}