Use override mechanism to disable Properties support

Instead of disable loading of Supervised entirly override initialization
to prevent loading the Properties interface.

supervisor/dbus/agent/boards/__init__.py

@@ -73,10 +73,8 @@ async def connect(self, bus: MessageBus) -> None:
             self._board_proxy = Yellow()
         elif self.board == BOARD_NAME_GREEN:
             self._board_proxy = Green()
-        # Currently unused, avoid initialization due to a bug in introspection:
-        # See: https://github.com/home-assistant/os-agent/issues/206
-        # elif self.board == BOARD_NAME_SUPERVISED:
-        #     self._board_proxy = Supervised()
+        elif self.board == BOARD_NAME_SUPERVISED:
+            self._board_proxy = Supervised()
         else:
             return
 

supervisor/dbus/agent/boards/supervised.py

@@ -1,5 +1,9 @@
 """Supervised board management."""
 
+from typing import Any
+
+from supervisor.dbus.utils import dbus_connected
+
 from .const import BOARD_NAME_SUPERVISED
 from .interface import BoardProxy
 
@@ -11,3 +15,11 @@ def __init__(self) -> None:
         """Initialize properties."""
         super().__init__(BOARD_NAME_SUPERVISED)
         self.sync_properties: bool = False
+
+    @dbus_connected
+    async def update(self, changed: dict[str, Any] | None = None) -> None:
+        """Do nothing as there are no properties.
+
+        Currently unused, avoid using the Properties interface to avoid a bug in
+        Go D-Bus, see: https://github.com/home-assistant/os-agent/issues/206
+        """