NextCloud crash when removing account

### ⚠️ 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

### Cause of error
```java
Exception in thread "main" java.lang.NullPointerException: Attempt to invoke interface method 'java.lang.String com.nextcloud.client.account.User.getAccountName()' on a null object reference
at com.owncloud.android.ui.activity.FileDisplayActivity.onStart(FileDisplayActivity.kt:2810)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1582)
at android.app.Activity.performStart(Activity.java:8628)
at android.app.ActivityThread.handleStartActivity(ActivityThread.java:3807)
at android.app.servertransaction.TransactionExecutor.performLifecycleSequence(TransactionExecutor.java:225)
at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:205)
at android.app.servertransaction.TransactionExecutor.cycleToPath(TransactionExecutor.java:187)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:96)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2443)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loopOnce(Looper.java:205)
at android.os.Looper.loop(Looper.java:294)
at android.app.ActivityThread.main(ActivityThread.java:8177)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:552)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:971)

```

### App information
* ID: `com.nextcloud.client`
* Version: `30340190`
* Build flavor: `gplay`

### Device information
* Brand: `google`
* Device: `bramble`
* Model: `Pixel 4a (5G)`
* Id: `UP1A.231105.001.B2`
* Product: `bramble`

### Firmware
* SDK: `34`
* Release: `14`
* Incremental: `11260668`

### Expected behaviour

Account should have been removed from the app without issue.

### Actual behaviour

App crashed and displayed a crash report.

### Android version

14

### Device brand and model

Google Pixel 4a 5G

### Stock or custom OS?

Stock

### Nextcloud android app version

3.34.1

### Nextcloud server version

32.0.2

### Using a reverse proxy?

Yes

### Android logs

_No response_

### Server error logs

```bash

```

### Additional information

_No response_