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.

test/test_editor.h

@@ -12,9 +12,7 @@ class TestEditor : public yaze::editor::Editor {
  public:
   TestEditor() = default;
   ~TestEditor() = default;
-  void Initialize() override {
-
-  }
+  void Initialize() override {}
 
   absl::Status Cut() override {
     return absl::UnimplementedError("Not implemented");