Refactor Renderer access and improve gesture handling in iOS and test files

- Replaced instances of Renderer::GetInstance() with Renderer::Get() for consistency across the codebase.
- Enhanced gesture handling in iOS by adding mouse position events for touch gestures.
- Streamlined test initialization for ImGui to align with recent renderer access changes.

src/ios/main.mm

@@ -87,8 +87,8 @@
   }
 
   ImGui_ImplSDL2_InitForSDLRenderer(_controller->window(),
-                                    yaze::core::Renderer::GetInstance().renderer());
-  ImGui_ImplSDLRenderer2_Init(yaze::core::Renderer::GetInstance().renderer());
+                                    yaze::core::Renderer::Get().renderer());
+  ImGui_ImplSDLRenderer2_Init(yaze::core::Renderer::Get().renderer());
 
   if (!LoadPackageFonts().ok()) {
     abort();