Chore: Replace go-multierror with errors package (#66432)

* code refactor and type assertions added to tests

* no-lint rule added for specific line

pkg/services/authn/authnimpl/service.go

@@ -6,7 +6,6 @@ import (
 	"net/http"
 	"strconv"
 
-	"github.com/hashicorp/go-multierror"
 	"github.com/prometheus/client_golang/prometheus"
 	"go.opentelemetry.io/otel/attribute"
 
@@ -143,7 +142,7 @@ func ProvideService(
 			connector, errConnector := socialService.GetConnector(name)
 			httpClient, errHTTPClient := socialService.GetOAuthHttpClient(name)
 			if errConnector != nil || errHTTPClient != nil {
-				s.log.Error("Failed to configure oauth client", "client", clientName, "err", multierror.Append(errConnector, errHTTPClient))
+				s.log.Error("Failed to configure oauth client", "client", clientName, "err", errors.Join(errConnector, errHTTPClient))
 			} else {
 				s.RegisterClient(clients.ProvideOAuth(clientName, cfg, oauthCfg, connector, httpClient))
 			}
@@ -201,7 +200,7 @@ func (s *Service) Authenticate(ctx context.Context, r *authn.Request) (*authn.Id
 					return nil, err
 				}
 
-				authErr = multierror.Append(authErr, err)
+				authErr = errors.Join(authErr, err)
 				// try next
 				continue
 			}