Two reports of m.call.hangup for each video call

### Steps to reproduce

Make a video call between two devices.

The homeserver uses generic_worker.

### Outcome

#### What did you expect?
On call hangup, there should be a single "Video call ended" message in the time line.

#### What happened instead?
Element Android shows two messages instead. Both the messages have a different party_id.

Element Desktop correctly shows a single "Video call ended".

### Your phone model

_No response_

### Operating system version

_No response_

### Application version and app store

Element version 1.4.25

### Homeserver

Synapse 1.61.1+focal1

### Will you send logs?

Yes

### Are you willing to provide a PR?

No