ui: fix keyboard.reset() to properly clear all interaction state (#36541)

fix keyboard.reset() to properly clear all interaction state

system/ui/widgets/keyboard.py

@@ -251,6 +251,10 @@ class Keyboard(Widget):
     if min_text_size is not None:
       self._min_text_size = min_text_size
     self._render_return_status = -1
+    self._last_shift_press_time = 0
+    self._backspace_pressed = False
+    self._backspace_press_time = 0.0
+    self._backspace_last_repeat = 0.0
     self.clear()