chore: Remove duplicated Joined dataclass

Author: maxblan

python/socha/api/protocol/protocol.py

@@ -268,21 +268,6 @@ class Meta:
     )
 
 
-@dataclass
-class Joined:
-    class Meta:
-        name = 'joined'
-
-    room_id: Optional[str] = field(
-        default=None,
-        metadata={
-            'name': 'roomId',
-            'type': 'Attribute',
-            'required': True,
-        },
-    )
-
-
 @dataclass
 class Left(ProtocolPacket):
     """