fix: show window on creation if specified (#7171)

I noticed that the popup window was not shown when choosing `Open
channel in a new popup window` in the right-click menu of the user
avatar in the UserInfoPopup and then found that `createWindow` did not
use `args.show`. This also affected the `/popup [channel]` command.

The bug was introduced in #7058.

Reviewed-by: pajlada <rasmus.karlsson@pajlada.com>
Parent-pr: 7058

src/singletons/WindowManager.cpp

@@ -374,7 +374,7 @@ Window &WindowManager::createWindow(WindowType type,
     }
 
     this->windows_.push_back(window);
-    if (args.parent)
+    if (args.show)
     {
         window->show();
     }