fix two errors about cupertino_text_field

com.unity.uiwidgets/Runtime/animation/listener_helpers.mixin.gen.cs

                 D.assert(() => {
                       IEnumerable<DiagnosticsNode> infoCollector() {
                           yield return new DiagnosticsProperty<AnimationLocalListenersMixinAnimationEagerListenerMixinAnimation<T>>(
-                              "The " + GetType() + " notifying listeners was:",
+                              "The " + GetType() + " notifying listeners was",
                               this,
                               style: DiagnosticsTreeStyle.errorProperty
                           );

com.unity.uiwidgets/Runtime/services/text_input.cs

             string text = "",
             TextSelection selection = null,
             TextRange composing = null) {
-            
+            selection = selection ?? TextSelection.collapsed(offset: -1);
             D.assert(text != null);
             D.assert(selection != null);
             this.text = text;