GraphServiceClient does not use authentication provider

Describe the bug

Describe the bug
Copying this bug from here as it seems to be an graph sdk issue:

I am using the following code to instantiate a GraphServiceClient. As I require to configure a http proxy I followed this example, see alternative 1 in code. Doing so the client will not aquire a token from the AuthenticationProvider and fails to connect, see Exception or Stack Trace.

Enforcing an Authorization header in the http client will fix the problem, see alternative 2.

Exception or Stack Trace
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'getGraphClient' defined in class path resource [xxxxxxxxxxxxxxxxx.class]: Failed to instantiate [com.microsoft.graph.serviceclient.GraphServiceClient]: Factory method 'getGraphClient' threw exception with message: Access token is empty.

To Reproduce
n.a.

Code Snippet

                assert (tenantId != null) : "Env var AZURE_TENANT_ID has not been provided.";
                assert (clientId != null) : "Env var AZURE_CLIENT_ID has not been provided.";
                assert (clientSecret != null) : "Env var AZURE_CLIENT_SECRET has not been provided.";
                assert (proxyHost != null) : "Env var PROXY_HOST has not been provided";
                assert (proxyPort != null) : "Env var PROXY_PORT has not been provided";

                logger.debug("tenant {}", tenantId);
                logger.debug("clientId {}", clientId);
                logger.debug("proxyHost {}", proxyHost);
                logger.debug("proxyPort {}", proxyPort);

                int proxyPortInt=0;
                try {
                        proxyPortInt = Integer.parseInt(proxyPort);
                } catch (NumberFormatException e) {
                        assert (false) : "Proxy port is not a valid integer";
                }

                // Example code taken from https://docs.microsoft.com/en-us/graph/sdks/customize-client?tabs=java#configuring-the-http-proxy-for-the-client
                InetSocketAddress address = new InetSocketAddress(proxyHost, proxyPortInt);
                ProxyOptions options = new ProxyOptions(ProxyOptions.Type.HTTP, address);
                HttpClient authClient = new NettyAsyncHttpClientBuilder().proxy(options)
                        .build();

                ClientSecretCredential credential = new ClientSecretCredentialBuilder()
                        .clientId(clientId)
                        .tenantId(tenantId)
                        .clientSecret(clientSecret)
                        .httpClient(authClient)
                        .build();

                String[] scopes = new String[]{"User.Read.All", "GroupMember.Read.All"};
                AzureIdentityAuthenticationProvider authProvider =
                        new AzureIdentityAuthenticationProvider(credential, List.of("login.microsoftonline.com").toArray(new String[0]), scopes);

                Proxy proxy = new Proxy(Proxy.Type.HTTP, address);

//                Alternative 2: It works with this code uncommented
//
//                OkHttpClient httpClient = GraphClientFactory.create().addInterceptor(chain -> {
//                        Request originalRequest = chain.request();
//
//                        // Get the access token
//                        String accessToken = Objects.requireNonNull(credential.getToken(
//                                                new TokenRequestContext()
//                                                        .addScopes("https://graph.microsoft.com/.default"))
//                                        .block())
//                                .getToken();
//
//                        // Add Authorization header
//                        Request authenticatedRequest = originalRequest.newBuilder()
//                                .header("Authorization", "Bearer " + accessToken)
//                                .build();
//
//                        return chain.proceed(authenticatedRequest);
//                }).proxy(proxy).build();
//             Alternative 2 end

//             Alternative 1: It should work with this code (comment if uncommenting block above!
                OkHttpClient httpClient = GraphClientFactory.create().proxy(proxy).build();
//             Alternative 1 end

                GraphServiceClient graphClient = new GraphServiceClient(authProvider, httpClient);

                GroupCollectionResponse res = graphClient.groups().get();

Expected behavior
Alternative 1 should work

Screenshots
n.a.

Setup (please complete the following information):

• OS: ubuntu

• IDE: Intellij

  // Include the sdk as a dependency
  implementation 'com.microsoft.graph:microsoft-graph:6.+'
  implementation 'com.azure:azure-identity:1.+'

  implementation 'org.springframework.boot:spring-boot-starter-web:3.4.4'
  providedRuntime 'org.springframework.boot:spring-boot-starter-tomcat:3.4.4'
  testImplementation 'org.springframework.boot:spring-boot-starter-test:3.4.4'

• Java version: 21

• App Server/Environment: Spring boot local execution

• Frameworks: Spring boot

Additional context
n.a.

Information Checklist
Kindly make sure that you have added all the following information above and checkoff the required fields otherwise we will treat the issuer as an incomplete report

• [/] Bug Description Added
• [/] Repro Steps Added
• [/] Setup information Added

Expected behavior

Alternative 1 should work

How to reproduce

See code snippet

SDK Version

microsoft-graph:6:34:0 microsoft-graph-core:3:6:1

Latest version known to work for scenario above?

No response

Known Workarounds

See code alternative 2

Debug output

</details>


### Configuration

Ubuntu 22.04
x86

### Other information

_No response_

從 GraphServiceClient(authProvider, httpClient) 的建構開始，追蹤 GraphClientFactory.create().proxy(proxy).build() 提供 HTTP 用戶端時 AzureIdentityAuthenticationProvider 的套用方式。重現提供的 Proxy 設定，並與可正常運作的 interceptor 替代方案進行比較。當驗證提供者不需要 workaround 即可提供 Authorization 標頭時，即表示完成。