test: add load test for session creation (#8088)

# Which Problems Are Solved

Extends load tests by testing session creation.

# How the Problems Are Solved

The test creates a session including a check for user id.

# Additional Context

- part of https://github.com/zitadel/zitadel/issues/7639

load-test/src/user.ts

@@ -171,6 +171,32 @@ export function addMachinePat(userId: string, org: Org, accessToken: string): Pr
   });
 }
 
+export type MachineSecret = {
+    clientId: string;
+    clientSecret: string;
+};
+
+const addMachineSecretTrend = new Trend('user_add_machine_secret_duration', true);
+export function addMachineSecret(userId: string, org: Org, accessToken: string): Promise<MachineSecret> {
+  return new Promise((resolve, reject) => {
+    let response = http.asyncRequest('PUT', url(`/management/v1/users/${userId}/secret`), null, {
+      headers: {
+        authorization: `Bearer ${accessToken}`,
+        'Content-Type': 'application/json',
+        'x-zitadel-orgid': org.organizationId,
+      },
+    });
+    response.then((res) => {
+      check(res, {
+        'generate machine secret status ok': (r) => r.status === 200,
+      }) || reject(`unable to generate machine secret (user id: ${userId}) status: ${res.status} body: ${res.body}`);
+
+      addMachineSecretTrend.add(res.timings.duration);
+      resolve(res.json()! as MachineSecret);
+    });
+  });
+}
+
 const lockUserTrend = new Trend('lock_user_duration', true);
 export function lockUser(userId: string, org: Org, accessToken: string): Promise<RefinedResponse<any>> {
   return new Promise((resolve, reject) => {