fix(Communities): make leaving communities work again

Turns out in https://github.com/status-im/status-desktop/commit/81bb7fcc6 we've introduced a regression where
leaving a communities isn't possible anymore because we're trying
to call an API that doesn't exist on the `chatsModel`.

This commit fixes it by ensuring the API is called from `chatsModel.communities`.

ui/app/AppLayouts/Chat/CommunityColumn.qml

@@ -81,7 +81,7 @@ Item {
                     icon.color: Style.current.red
                     icon.width: 20
                     icon.height: 20
-                    onTriggered: chatsModel.leaveCurrentCommunity()
+                    onTriggered: chatsModel.communities.leaveCurrentCommunity()
                 }
 
                 onAboutToHide: {