tidy up event handler

src/components/structures/MatrixChat.tsx

@@ -1373,17 +1373,19 @@ export default class MatrixChat extends React.PureComponent<IProps, IState> {
                 ready: true,
             });
         });
-        cli.on('Call.incoming', function(call) {
-            // Check if the VoIP UI has been disabled
-            if (!SettingsStore.getValue(UIFeature.Voip)) return;
-            // we dispatch this synchronously to make sure that the event
-            // handlers on the call are set up immediately (so that if
-            // we get an immediate hangup, we don't get a stuck call)
-            dis.dispatch({
-                action: 'incoming_call',
-                call: call,
-            }, true);
-        });
+
+        if (SettingsStore.getValue(UIFeature.Voip)) {
+            cli.on('Call.incoming', function(call) {
+                // we dispatch this synchronously to make sure that the event
+                // handlers on the call are set up immediately (so that if
+                // we get an immediate hangup, we don't get a stuck call)
+                dis.dispatch({
+                    action: 'incoming_call',
+                    call: call,
+                }, true);
+            });
+        }
+
         cli.on('Session.logged_out', function(errObj) {
             if (Lifecycle.isLoggingOut()) return;