Fix client authenticator option

[rbrt-sln]

The gremlin client config requires an authenticator field, as described in the Tinkerpop documentation (source code can be found here).

It is currently writen as credentials and reflected in the Azure Gremlin Quickstart for Node.js, causing the quickstart tutorial to fail with:

/workspaces/cosmos-db-apache-gremlin-javascript-samples/001-quickstart/node_modules/gremlin/lib/driver/connection.js:318
        new ResponseError(`Server error: ${response.status.message} (${response.status.code})`, response.status),
        ^

ResponseError: Server error: ActivityId: ...
Gremlin server SASL authentication challenge. (407)
    at #handleMessage (/workspaces/cosmos-db-apache-gremlin-javascript-samples/001-quickstart/node_modules/gremlin/lib/driver/connection.js:318:9)
    at callListener (/workspaces/cosmos-db-apache-gremlin-javascript-samples/001-quickstart/node_modules/ws/lib/event-target.js:290:14)
    at WebSocket.onMessage (/workspaces/cosmos-db-apache-gremlin-javascript-samples/001-quickstart/node_modules/ws/lib/event-target.js:209:9)
    at WebSocket.emit (node:events:519:28)
    at Receiver.receiverOnMessage (/workspaces/cosmos-db-apache-gremlin-javascript-samples/001-quickstart/node_modules/ws/lib/websocket.js:1209:20)
    at Receiver.emit (node:events:519:28)
    at Receiver.dataMessage (/workspaces/cosmos-db-apache-gremlin-javascript-samples/001-quickstart/node_modules/ws/lib/receiver.js:567:14)
    at Receiver.getData (/workspaces/cosmos-db-apache-gremlin-javascript-samples/001-quickstart/node_modules/ws/lib/receiver.js:496:10)
    at Receiver.startLoop (/workspaces/cosmos-db-apache-gremlin-javascript-samples/001-quickstart/node_modules/ws/lib/receiver.js:167:16)
    at Receiver._write (/workspaces/cosmos-db-apache-gremlin-javascript-samples/001-quickstart/node_modules/ws/lib/receiver.js:94:10) {
  statusCode: 407,
  statusMessage: 'ActivityId: ...\n' +
    'Gremlin server SASL authentication challenge.',
  statusAttributes: { 'x-ms-activity-id': '...' }
}