fix failing text e.g. restore carretIndex in textbox when text changed

src/Avalonia.Controls/TextBox.cs

@@ -212,9 +212,10 @@ namespace Avalonia.Controls
             {
                 if (!_ignoreTextChanges)
                 {
-                    CaretIndex = CoerceCaretIndex(CaretIndex, value?.Length ?? 0);
+                    var carretIndex = CaretIndex;
                     SelectionStart = CoerceCaretIndex(SelectionStart, value?.Length ?? 0);
                     SelectionEnd = CoerceCaretIndex(SelectionEnd, value?.Length ?? 0);
+                    CaretIndex = CoerceCaretIndex(carretIndex, value?.Length ?? 0);
 
                     if (SetAndRaise(TextProperty, ref _text, value) && !_isUndoingRedoing)
                     {