Allow rotation of rectangles and ellipses (#7682)

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Added the ability to rotate rectangles and ellipses. Similar to the
existing text implementation

* [x ] I have followed the instructions in the PR template

crates/egui_demo_lib/src/demo/tests/tessellation_test.rs

@@ -297,6 +297,7 @@ fn rect_shape_ui(ui: &mut egui::Ui, shape: &mut RectShape) {
         blur_width,
         round_to_pixels,
         brush: _,
+        angle: _,
     } = shape;
 
     let round_to_pixels = round_to_pixels.get_or_insert(true);