Protect against NaN in hit-test code (#6851)

* Closes <https://github.com/emilk/egui/issues/6756>
* [x] I have followed the instructions in the PR template

crates/egui/src/hit_test.rs

@@ -65,7 +65,7 @@ pub fn hit_test(
         .filter(|layer| layer.order.allow_interaction())
         .flat_map(|&layer_id| widgets.get_layer(layer_id))
         .filter(|&w| {
-            if w.interact_rect.is_negative() {
+            if w.interact_rect.is_negative() || w.interact_rect.any_nan() {
                 return false;
             }