Change custom_app_url to port 7860 for Reachy Mini settings

Reachy Mini apps use port 7860 for settings UI by default.
This matches the standard port used by other Reachy Mini apps.

reachy_mini_ha_voice/app.py

@@ -46,7 +46,7 @@ _SOUNDS_DIR = _REPO_DIR / "sounds"
 class ReachyMiniHAVoiceApp(ReachyMiniApp):
     """Home Assistant Voice Assistant for Reachy Mini."""
 
-    custom_app_url: Optional[str] = "http://0.0.0.0:8042"
+    custom_app_url: Optional[str] = "http://0.0.0.0:7860"
 
     def __init__(self):
         """Initialize the app."""