GQL_CONNECTION_ERROR being sent from Client -> Server on exception during client connection

[tcheard]

GQL_CONNECTION_ERROR (connection_error) is defined as a Server -> Client message type:

https://github.com/apollographql/subscriptions-transport-ws/blob/faa219cff7b6f9873cae59b490da46684d7bea19/PROTOCOL.md#gql_connection_error

subscriptions-transport-ws/src/message-types.ts

Line 4 in faa219c

public static GQL_CONNECTION_ERROR = 'connection_error'; // Server -> Client

Yet if an exception occurs while setting up connection params or sending the connection_init, this message type is sent from Client -> Server:

subscriptions-transport-ws/src/client.ts

Line 562 in cf3f492

this.sendMessage(undefined, MessageTypes.GQL_CONNECTION_ERROR, error);

If the client can't set up a connection, it likely shouldn't be sending a connection_error message to the server.