chore: move gofakeit integration testing calls (#10684)

# Which Problems Are Solved

Flakiness and conflicts in value from gofakeit.

# How the Problems Are Solved

Move Gofakeit calls to the integration package, to guarantee proper
usage and values for integration testing.

# Additional Changes

None

# Additional Context

None

(cherry picked from commit 492f1826ee)

internal/api/oidc/integration_test/token_client_credentials_test.go

@@ -7,7 +7,6 @@ import (
 	"testing"
 	"time"
 
-	"github.com/brianvoe/gofakeit/v6"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 	"github.com/zitadel/oidc/v3/pkg/client/rp"
@@ -62,7 +61,7 @@ func TestServer_ClientCredentialsExchange(t *testing.T) {
 		{
 			name: "machine user without secret error",
 			clientID: func() string {
-				name := gofakeit.Username()
+				name := integration.Username()
 				_, err := Instance.Client.Mgmt.AddMachineUser(CTX, &management.AddMachineUserRequest{
 					Name:            name,
 					UserName:        name,