Revert "add ui_update callback"

This reverts commit 4da32cc009.

selfdrive/ui/sunnypilot/ui_state.py

@@ -1,5 +1,3 @@
-from collections.abc import Callable
-
 from openpilot.selfdrive.ui.ui_state import UIState
 from cereal import messaging
 from openpilot.common.params import Params
@@ -19,16 +17,8 @@ class UIStateSP(UIState):
     ]
     self.sm = messaging.SubMaster(op_services + sp_services)
 
-    # Callbacks
-    self._ui_update_callbacks: list[Callable[[], None]] = []
-
-  def add_ui_update_callback(self, callback: Callable[[], None]):
-    self._ui_update_callbacks.append(callback)
-
   def update(self) -> None:
     UIState.update(self)
-    for callback in self._ui_update_callbacks:
-      callback()
 
   def _update_status(self) -> None:
     UIState._update_status(self)