Contact Restore causes crash: `com.owncloud.android.ui.fragment.contactsbackup.ContactsAccount.getName()' on a null object reference`

### ⚠️ Before posting ⚠️

- [X] This is a **bug**, not a question or an enhancement.
- [X] I've [searched for similar issues](https://github.com/nextcloud/android/issues) and didn't find a duplicate.
- [X] I've written a clear and descriptive title for this issue, not just "Bug" or "Crash".
- [X] I agree to follow Nextcloud's [Code of Conduct](https://nextcloud.com/contribute/code-of-conduct/).

### Steps to reproduce

Settings>Contacts & calendar backup>Restore Contacts>Select any date and any contact

### Expected behaviour

Copy contact from backup

### Actual behaviour

Does not restore and provides a bug report.

### Android version

13

### Device brand and model

Google Pixel 5

### Stock or custom OS?

Stock

### Nextcloud android app version

3.24.1

### Nextcloud server version

25.0.1

### Using a reverse proxy?

Yes

### Android logs

### Cause of error
```java
Exception in thread "main" java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.owncloud.android.ui.fragment.contactsbackup.ContactsAccount.getName()' on a null object reference
at com.owncloud.android.ui.fragment.contactsbackup.BackupListFragment.importContacts(BackupListFragment.java:352)
at com.owncloud.android.ui.fragment.contactsbackup.BackupListFragment.lambda$onCreateView$0$com-owncloud-android-ui-fragment-contactsbackup-BackupListFragment(BackupListFragment.java:236)
at com.owncloud.android.ui.fragment.contactsbackup.BackupListFragment$$ExternalSyntheticLambda1.onClick(Unknown Source:2)
at android.view.View.performClick(View.java:7506)
at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:1219)
at android.view.View.performClickInternal(View.java:7483)
at android.view.View.-$$Nest$mperformClickInternal(Unknown Source:0)
at android.view.View$PerformClick.run(View.java:29341)
at android.os.Handler.handleCallback(Handler.java:942)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loopOnce(Looper.java:201)
at android.os.Looper.loop(Looper.java:288)
at android.app.ActivityThread.main(ActivityThread.java:7872)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:936)

```

### App information
* ID: `com.nextcloud.client`
* Version: `30240190`
* Build flavor: `gplay`

### Device information
* Brand: `google`
* Device: `redfin`
* Model: `Pixel 5`
* Id: `TQ1A.230205.002`
* Product: `redfin`

### Firmware
* SDK: `33`
* Release: `13`
* Incremental: `9471150`

### Server error logs

_No response_

### Additional information

_No response_