refactor: reformat CompatGrpcTransport constructor parameters for conciseness.

Author: guglielmo-san

src/a2a/compat/v0_3/grpc_transport.py

@@ -85,11 +85,7 @@ async def wrapper(*args: Any, **kwargs: Any) -> Any:
 class CompatGrpcTransport(ClientTransport):
     """A backward compatible gRPC transport for A2A v0.3."""
 
-    def __init__(
-        self,
-        channel: Channel,
-        agent_card: a2a_pb2.AgentCard | None
-    ):
+    def __init__(self, channel: Channel, agent_card: a2a_pb2.AgentCard | None):
         """Initializes the CompatGrpcTransport."""
         self.agent_card = agent_card
         self.channel = channel