Add a cancel location sharing button in the notification bubble while user is sharing their location

There already exists a button which when clicked, cancels location sharing. But the cancellation should be handled properly and `stopLocationSharing()` method must be called from there so that the data is saved to firebase.
```kotlin
val cancelIntent = Intent(this, ForegroundOnlyLocationService::class.java)
cancelIntent.putExtra(EXTRA_CANCEL_LOCATION_TRACKING_FROM_NOTIFICATION, true)

val servicePendingIntent = PendingIntent.getService(
this, 0, cancelIntent, PendingIntent.FLAG_UPDATE_CURRENT
)
```