fix: use ClientSecretCredential instead of DefaultAzureCredential in graph-connector template (#15416)

* Initial plan

* fix: not use DefaultAzureCredential but use ClientSecretCredential

Co-authored-by: Alive-Fish <15262146+Alive-Fish@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Alive-Fish <15262146+Alive-Fish@users.noreply.github.com>

Author: Copilot

templates/vsc/ts/graph-connector/src/graphClient.ts

@@ -1,4 +1,4 @@
-import { DefaultAzureCredential } from "@azure/identity";
+import { ClientSecretCredential } from "@azure/identity";
 import { Client, MiddlewareFactory } from "@microsoft/microsoft-graph-client";
 import { TokenCredentialAuthenticationProvider } from "@microsoft/microsoft-graph-client/authProviders/azureTokenCredentials/index.js";
 import { LongRunningOperationMiddleware } from "./longRunningOperationMiddleware";
@@ -10,9 +10,11 @@ const delayInterval = 60_000; // 60 seconds
  * @returns A new instance of the Microsoft Graph client.
  */
 export function getClient(): Client {
-  const credential = new DefaultAzureCredential({
-    requiredEnvVars: ["AZURE_TOKEN_CREDENTIALS"],
-  });
+  const credential = new ClientSecretCredential(
+    process.env.AZURE_TENANT_ID!,
+    process.env.AZURE_CLIENT_ID!,
+    process.env.AZURE_CLIENT_SECRET!
+  );
 
   const authProvider = new TokenCredentialAuthenticationProvider(credential, {
     scopes: ["https://graph.microsoft.com/.default"],