HackStudio+LibGUI: Make fallible TabWidget::add_tab() non-fallible

Author: https://github.com/tcl3
Commit: 499f459f0b
Pull-request: https://github.com/SerenityOS/serenity/pull/21067
Reviewed-by: https://github.com/AtkinsSJ ✅
Reviewed-by: https://github.com/shannonbooth ✅

Userland/Libraries/LibGUI/TabWidget.h

@@ -64,11 +64,10 @@ public:
         return *t;
     }
 
-    ErrorOr<void> add_tab(NonnullRefPtr<Widget> const& tab, String title)
+    void add_tab(NonnullRefPtr<Widget> const& tab, String title)
     {
         tab->set_title(move(title));
-        TRY(try_add_widget(*tab));
-        return {};
+        add_widget(*tab);
     }
 
     void remove_tab(Widget& tab) { remove_widget(tab); }