Update enrollAuthFactor method (#903)

## Description

## Documentation

Does this require changes to the WorkOS Docs? E.g. the [API
Reference](https://workos.com/docs/reference) or code snippets need
updates.

```
[ ] Yes
```

If yes, link a related docs PR and add a docs maintainer as a reviewer.
Their approval is required.



#### PR Dependency Tree


* **PR #903** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

src/user-management/interfaces/enroll-auth-factor.interface.ts

@@ -1,12 +1,12 @@
 export interface EnrollAuthFactorOptions {
   userId: string;
   type: 'totp';
-  totpIssuer: string;
-  totpUser: string;
+  totpIssuer?: string;
+  totpUser?: string;
 }
 
 export interface SerializedEnrollUserInMfaFactorOptions {
   type: 'totp';
-  totp_issuer: string;
-  totp_user: string;
+  totp_issuer?: string;
+  totp_user?: string;
 }

src/user-management/user-management.spec.ts

@@ -376,7 +376,7 @@ describe('UserManagement', () => {
 
   describe('enrollAuthFactor', () => {
     it('sends an enrollAuthFactor request', async () => {
-      mock.onPost(`/user_management/${userId}/auth/factors`).reply(200, {
+      mock.onPost(`/user_management/users/${userId}/auth_factors`).reply(200, {
         authentication_factor: {
           object: 'authentication_factor',
           id: 'auth_factor_1234',
@@ -410,7 +410,7 @@ describe('UserManagement', () => {
       });
 
       expect(mock.history.post[0].url).toEqual(
-        `/user_management/${userId}/auth/factors`,
+        `/user_management/users/${userId}/auth_factors`,
       );
       expect(resp).toMatchObject({
         authenticationFactor: {

src/user-management/user-management.ts

@@ -294,7 +294,7 @@ export class UserManagement {
       authentication_factor: FactorResponse;
       authentication_challenge: ChallengeResponse;
     }>(
-      `/user_management/${payload.userId}/auth/factors`,
+      `/user_management/users/${payload.userId}/auth_factors`,
       serializeEnrollAuthFactorOptions(payload),
     );