NPE on upload cancel in `UploadNotificationActionReceiver`

### ⚠️ 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

1. Having a folder registered for auto upload
2. Set signal to use this folder as backup folder
3. Create a backup
4. Wait for nextcloud upload notification
5. Cancel it

### Expected behaviour

Canceled upload. Removal of temporary file on nextcloud side

### Actual behaviour

I'm getting this error and trace

### Cause of error
```java
Exception in thread "main" java.lang.RuntimeException: Unable to start receiver com.owncloud.android.files.services.FileUploader$UploadNotificationActionReceiver: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.owncloud.android.files.services.FileUploader$FileUploaderBinder.cancel(java.lang.String, java.lang.String, com.owncloud.android.lib.common.operations.RemoteOperationResult$ResultCode)' on a null object reference
at android.app.ActivityThread.handleReceiver(ActivityThread.java:5117)
at android.app.ActivityThread.-$$Nest$mhandleReceiver(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2682)
at android.os.Handler.dispatchMessage(Handler.java:114)
at android.os.Looper.loopOnce(Looper.java:206)
at android.os.Looper.loop(Looper.java:296)
at android.app.ActivityThread.main(ActivityThread.java:9159)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:591)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1018)
Caused by: Exception in thread "main" java.lang.NullPointerException: Attempt to invoke virtual method 'void com.owncloud.android.files.services.FileUploader$FileUploaderBinder.cancel(java.lang.String, java.lang.String, com.owncloud.android.lib.common.operations.RemoteOperationResult$ResultCode)' on a null object reference
at com.owncloud.android.files.services.FileUploader$UploadNotificationActionReceiver.onReceive(FileUploader.java:1521)
at android.app.ActivityThread.handleReceiver(ActivityThread.java:5108)
at android.app.ActivityThread.-$$Nest$mhandleReceiver(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2682)
at android.os.Handler.dispatchMessage(Handler.java:114)
at android.os.Looper.loopOnce(Looper.java:206)
at android.os.Looper.loop(Looper.java:296)
at android.app.ActivityThread.main(ActivityThread.java:9159)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:591)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1018)

```

### App information
* ID: `com.nextcloud.client`
* Version: `30270090`
* Build flavor: `gplay`

### Device information
* Brand: `HONOR`
* Device: `HNFRI`
* Model: `FRI-NX9`
* Id: `HONORFRI-N39`
* Product: `FRI-NX9EEA`

### Firmware
* SDK: `33`
* Release: `13`
* Incremental: `7.1.0.166C430E9R3P1`

### Android version

13

### Device brand and model

Honor magic VS

### Stock or custom OS?

Stock

### Nextcloud android app version

3.27.0

### Nextcloud server version

27.1.5

### Using a reverse proxy?

No

### Android logs

_No response_

### Server error logs

_No response_

### Additional information

It may be due to the .backup*.temp file behind uploaded WHILE signal is doing the backup.