Ensure the splash group always exists

so we can call pycam.display_message even without the rest of the camera
ui

Author: jepler

adafruit_pycamera/__init__.py

@@ -198,7 +198,7 @@ def __init__(self) -> None:  # pylint: disable=too-many-statements
         self.display = None
         self.pixels = None
         self.sdcard = None
-        self.splash = None
+        self.splash = displayio.Group()
 
         # Reset display and I/O expander
         self._tft_aw_reset = DigitalInOut(board.TFT_RESET)
@@ -246,7 +246,6 @@ def make_debounced_expander_pin(pin_no):
 
     def make_camera_ui(self):
         """Create displayio widgets for the standard camera UI"""
-        self.splash = displayio.Group()
         self._sd_label = label.Label(
             terminalio.FONT, text="SD ??", color=0x0, x=150, y=10, scale=2
         )