Don't pass basic auth to password cluster HTTP calls. (#823)

When we pass basic auth, this gets used as the `Authorization` header. 

We don't actually need this for anything... the `ssh_user` and `password` should only be needed to create the `ssh_tunnel`, so let's just not send this at all.

runhouse/resources/hardware/cluster.py

@@ -596,17 +596,12 @@ def connect_server_client(self, force_reconnect=False):
             )
             self.client_port = self._rpc_tunnel.local_bind_port
 
-            ssh_user = self.creds_values.get("ssh_user")
-            password = self.creds_values.get("password")
-            auth = (ssh_user, password) if ssh_user and password else None
-
             # Connecting to localhost because it's tunneled into the server at the specified port.
             # As long as the tunnel was initialized,
             # self.client_port has been set to the correct port
             self.client = HTTPClient(
                 host=LOCALHOST,
                 port=self.client_port,
-                auth=auth,
                 resource_address=self.rns_address,
                 system=self,
             )