recreating a user account doesn't create a new pushtoken

### Steps to reproduce
1. create a test account on your NC21.0.4 instance with name `test`
2. log in with the android app 3.17.0 to this account
3. run `select * from oc_notifications_pushtokens where uid = 'test';` on your database which shows the newly created pushtoken
4. delete the account again from the android app
5. log in with the android app again with the same account
6. run `select * from oc_notifications_pushtokens where uid = 'test';` on your database which doesn't show a new pushtoken

### Expected behaviour
- Recreating an account should create a new pushtoken

### Actual behaviour
- recreating the account doens't create a new pushtoken

### Environment data
Android version: reproduced on android 8 and 11

Device model: Samsung Galaxy S10e and Sony Xperia X Performance

Stock or customized system: both stock

Nextcloud app version: 3.17.0

Nextcloud server version: 21.0.4

Reverse proxy: no

### Logs
#### Web server error log
```
Not related
```

#### Nextcloud log (data/nextcloud.log)
```
No error logged
```