only add circuitpython_splash to display if it's not already in another group

Author: FoamyGuy

shared-module/displayio/Display.c

@@ -136,7 +136,9 @@ void common_hal_displayio_display_construct(displayio_display_obj_t *self,
 
     // Set the group after initialization otherwise we may send pixels while we delay in
     // initialization.
-    common_hal_displayio_display_set_root_group(self, &circuitpython_splash);
+    if (!circuitpython_splash.in_group) {
+        common_hal_displayio_display_set_root_group(self, &circuitpython_splash);
+    }
     common_hal_displayio_display_set_auto_refresh(self, auto_refresh);
 }