Notifications not working, even though "listening for notifications" [F-Droid; Huawei P30]

### Steps to reproduce

I am using the most recent version of Element on an android Huawei P30 phone. Notifications work on another phone of mine fine, and I have painstakingly gone through every single notifications/battery setting that I could find. I even went through the "Troubleshoot notifications" menu item, which showed that everything was working fine.

Symptoms
* In the system notifications, there is a notification saying "Element. Listening for notifications. 1 min ago." Sending a message to the person however does not trigger any notifications.
* Even when the Element app is open in the foreground, no notifications appears.

I note that this issue is different that some other people, where notifications work fine only when the app is open and running in the foreground.

### Outcome

Not working.

### Your phone model

Huawei P30: ELE-L29

### Operating system version

12.0.0

### Application version and app store

1.4.36 [40104360] (F-6cada8f6)

### Homeserver

matrix.org

### Will you send logs?

Yes

### Are you willing to provide a PR?

No