Text: duplicate during a text edit leaves no effect selected on the original (#2226)

Duplicate passes over the property selection an open edit kept and copies the edited layer,
but left that selection in place on the original. With the copy selected, the next Duplicate
copied the original's effect, shape item or text animator, and Clear would have removed it.
Ending the edit through Duplicate now clears that property selection along with it.

crates/engine/src/tests/text_edit.rs

@@ -1265,11 +1265,16 @@ fn duplicate_during_an_edit_copies_the_layer_not_a_selected_property_group() {
         assert_eq!(items(&s).len(), n, "{what}: the selected {what} is not duplicated");
         assert_eq!(layers(&s), before + 1, "{what}: the edited layer is");
         assert_eq!(s.state.selected_layers, vec![LayerId(r[0].as_u64().unwrap())], "{what}: and its copy is selected");
+        // The selection the edit passed over goes with it: the next Duplicate copies the selected
+        // copy rather than reaching back to the original's {what}.
+        s.execute("edit.duplicate", json!({})).unwrap();
+        assert_eq!(items(&s).len(), n, "{what}: a second Duplicate leaves the original's {what} alone");
+        assert_eq!(layers(&s), before + 2, "{what}: and copies the copy");
         // With no edit open, the selected item keeps its precedence over the layers.
         s.execute("prop.select", json!({"layer": owner, "prop": item})).unwrap();
         s.execute("edit.duplicate", json!({})).unwrap();
         assert_eq!(items(&s).len(), n + 1, "{what}: outside an edit Duplicate copies the selected {what}");
-        assert_eq!(layers(&s), before + 1, "{what}: and no layer");
+        assert_eq!(layers(&s), before + 2, "{what}: and no layer");
     }
 }