[FR]: How to notify LiveUpdate when app is closed via FCM

### Is there an existing FR for this?

- [x] I have searched the existing issues

### For which area is this FR?

User Interface

### Is it for a specific sample?

_No response_

### Describe the feature request

I’m currently working on LiveUpdates integration.

I’m using FCM to receive instructions and then call `NotificationManager.notify(state)` to display or update LiveUpdates. However, I’ve encountered a few scenarios where the app is unable to actively control the LiveUpdate state:

1. When there’s an existing LiveUpdate shown in the notification center and the app is closed, how can we update that LiveUpdate?
2. If the LiveUpdate has already reached 100% progress, how can the app automatically dismiss it after a certain amount of time?
3. As far as I know, iOS LiveActivity uses FCM/APNs to remotely end an activity. Will Android LiveUpdates follow a similar approach?

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct

Start by tracing the LiveUpdates integration described in the issue, focusing on FCM and NotificationManager.notify(state). Determine whether the project has an existing sample or entry point for updates while the app is closed, automatic dismissal, or remote ending. Done requires a decided Android approach that addresses all three scenarios.

Written by the indexing model from the issue text.