Support data plane RBAC for Gremlin API (#2182)

* Refactor logic for determining if we should use data plane RBAC to a
common function.

* Support RBAC for gremlin API.

* Refactor to use common function.

* Fix unit tests.

* Move test function inside test scope.

* Minor clean ups.

* Reinstate utf8ToB64 function in case this breaks a corner case.

src/Explorer/DataSamples/ContainerSampleGenerator.ts

@@ -1,3 +1,4 @@
+import { useDataplaneRbacAuthorization } from "Utils/AuthorizationUtils";
 import { createCollection } from "../../Common/dataAccess/createCollection";
 import { createDocument } from "../../Common/dataAccess/createDocument";
 import { createDocument as createMongoDocument } from "../../Common/MongoProxyClient";
@@ -90,12 +91,13 @@ export class ContainerSampleGenerator {
       }
       const { databaseAccount: account } = userContext;
       const databaseId = collection.databaseId;
+
       const gremlinClient = new GremlinClient();
       gremlinClient.initialize({
         endpoint: `wss://${GraphTab.getGremlinEndpoint(account)}`,
         databaseId: databaseId,
         collectionId: collection.id(),
-        masterKey: userContext.masterKey || "",
+        password: useDataplaneRbacAuthorization(userContext) ? userContext.aadToken : userContext.masterKey || "",
         maxResultSize: 100,
       });