Call hangup needs a soundeffect

### Your use case

#### What would you like to do?
When me or my friend hangs up a call there is currently no sound effect or indication the call is over other than the part of the gui that deals with the call no longer being there and the text 'call ended' next to the call in the chat history.
#### Why would you like to do it?
I feel this is insufficient especially while me and my friend are collaborating on something else and therefore the window is minimized. If the call dropped accidentally or one of us hangs up on the other, there is currently no indication that this has happened on audio so no easy way to know this has happened without manually checking, which you may not have a reason to do unless you notice they haven't said anything in a while.
#### How would you like to achieve it?
Add a sound effect to the call hangup function.

### Have you considered any alternatives?

_No response_

### Additional context

_No response_

No implementation repository, files, tests, or entry points are identified in the issue. First locate the call hangup flow and any existing call audio feedback in the relevant Element client, then determine how to cover local hangups, remote hangups, accidental drops, and minimized windows; done means a sound clearly indicates that the call has ended.

Written by the indexing model from the issue text.