Update Juno endpoints to pass subscriptionId (#339)

Corresponding [server side change](https://msdata.visualstudio.com/CosmosDB/_git/CosmosDB-portal/pullrequest/464443?_a=overview) has been deployed to Prod so now we can go ahead with DE side changes.

src/Juno/JunoClient.test.ts

@@ -248,7 +248,7 @@ describe("Gallery", () => {
     const authorizationHeader = getAuthorizationHeader();
     expect(response.status).toBe(HttpStatusCodes.OK);
     expect(window.fetch).toBeCalledWith(
-      `${configContext.JUNO_ENDPOINT}/api/notebooks/${sampleDatabaseAccount.name}/gallery/${id}/favorite`,
+      `${configContext.JUNO_ENDPOINT}/api/notebooks/${sampleSubscriptionId}/${sampleDatabaseAccount.name}/gallery/${id}/favorite`,
       {
         method: "PATCH",
         headers: {