Element-android: Don't set presence when handling a push notification or polling

[jcgruenhage]

Describe the bug
Element is setting the client as online on each notification when using GCM, or always when polling in the F-Droid flavour. This sort of defeats the purpose of the presence feature.

To Reproduce
Steps to reproduce the behavior:

1. Have Element Android on one account, close the app.
2. Send them a message from some client
3. See them coming online immediately, without opening the app.

Expected behavior

1. Have Element Android on one account, close the app.
2. Send them a message from some client
3. See them coming online only when they actually open the app

In the case of the F-Droid flavour, as long as the app is syncing in the background, the account is just never, ever displayed as offline.

Additional context
The solution is to use the set_presence parameter on the /sync request unless the app is open.

[violoncelloCH]

related to #70 and #1521

[bmarty]

Yes, presence is still not implemented. I'm thinking about working on it :)

[jcgruenhage]

There's two parts to presence here: Showing presence of others, as well as actively setting presence to online when using the app. That'dbe a feature request. The other part, setting presence to online du to sync request when the app is not open is a bug IMO, and should have a higher priority than presence as a feature.

Very nice to hear that you intend to implement presence as a feature too though