Toast needed for Element Call Decline event

### Steps to reproduce

1. Call a remote user using EC
2. Remote device starts to ring
3. User on the remote device rejects the call
4. Calling device drops the call

### Outcome

#### What did you expect?
A feedback should appear that the remote device has rejected the call
#### What happened instead?
EC simply closes the session

There is no way to know if the call got dropped because the ring time ran out or the call was rejected. The user needs to know that the call was rejected so can be polite and dont call again.

### Your phone model

_No response_

### Operating system version

_No response_

### Application version and app store

Element 25.12.0

### Homeserver

_No response_

### Will you send logs?

No

### Are you willing to provide a PR?

No