Fix bug where calls could break if rejected from somewhere else (#2189)

* Fix bug where calls could ignore new events of rejected from somewhere else

When callEventHandler passed a reject event to the call object, it assumed
that always caused the call to end and deleted it from the list, so it
never got any more events. The point of a reject is that it doesn't
end the call if it's already been picked up though. This only removes
the call if it's actually ended.

* Use ts-expect-error

src/webrtc/callEventHandler.ts

@@ -257,7 +257,11 @@ export class CallEventHandler {
                     } else {
                         call.onRejectReceived(content as MCallHangupReject);
                     }
-                    this.calls.delete(content.call_id);
+
+                    // @ts-expect-error typescript thinks the state can't be 'ended' because we're
+                    // inside the if block where it wasn't, but it could have changed because
+                    // on[Hangup|Reject]Received are side-effecty.
+                    if (call.state === CallState.Ended) this.calls.delete(content.call_id);
                 }
             }
             return;