Don't require name for list commands

The name argument is not required when a listing of devices is
requested.

linux_voice_assistant/__main__.py

@@ -33,7 +33,7 @@ _SOUNDS_DIR = _REPO_DIR / "sounds"
 
 async def main() -> None:
     parser = argparse.ArgumentParser()
-    parser.add_argument("--name", required=True)
+    parser.add_argument("--name")
     parser.add_argument(
         "--audio-input-device",
         help="soundcard name for input device (see --list-input-devices)",
@@ -118,6 +118,9 @@ async def main() -> None:
     logging.basicConfig(level=logging.DEBUG if args.debug else logging.INFO)
     _LOGGER.debug(args)
 
+    if not args.name:
+        parser.error("the following arguments are required: --name")
+
     args.download_dir = Path(args.download_dir)
     args.download_dir.mkdir(parents=True, exist_ok=True)