Minor remaining fixes for PR (#4374)

- changed case of `handleNoModLoader` to match project style

- made default case in switch statement for `handleNoModLoader` return
  true for safety

Signed-off-by: Pagwin <dev@pagwin.xyz>

launcher/ui/pages/instance/ModFolderPage.h

@@ -45,7 +45,7 @@
 class ModFolderPage : public ExternalResourcesPage {
     Q_OBJECT
 
-    bool HandleNoModLoader();
+    inline bool handleNoModLoader();
 
    public:
     explicit ModFolderPage(BaseInstance* inst, std::shared_ptr<ModFolderModel> model, QWidget* parent = nullptr);