[Bug]: The app is still running in background event if it's killed

### Please check the following before submitting a new issue.

- [X] I have searched the [existing issues](https://github.com/baseflow/flutter-geolocator/issues).
- [X] I have carefully [read the documentation](https://github.com/Baseflow/flutter-geolocator/blob/main/geolocator/README.md) and verified I have added the required platform specific configuration.

### Please select affected platform(s)

- [X] Android
- [ ] iOS
- [ ] Linux
- [ ] macOS
- [ ] Web
- [ ] Windows

### Steps to reproduce

Just have notification configured and run the app. When you kill it you get:
`There is still another flutter engine connected, not stopping location service`

### Expected results

The app should be killed and notification should be removed

### Actual results

The app still is running and notification is still there. This is draining users battery.

### Code sample

Code sample

```dart
[Paste your code here]
```

### Screenshots or video

Screenshots or video demonstration

[Upload media here]

### Version

10.1.0

### Flutter Doctor output

Doctor output

```console
[Paste your output here]
```

Start by reproducing the Android case with notification configured, using the reported message about another Flutter engine and the location service. Trace the Android location service and notification shutdown path, then verify that killing the app stops the service and removes the notification without continuing battery use.

Written by the indexing model from the issue text.