feat(auth): verify API client connectivity in set_api_client

  Add an authentication check when setting a custom API client to
  catch misconfigured or invalid clients early. The verification
  calls AuthenticationApi.get_api_group() to confirm the client
  can reach the Kubernetes API server before proceeding.

Signed-off-by: Saad Zaher <szaher@redhat.com>

Author: szaher

src/codeflare_sdk/common/kubernetes_cluster/auth.py

@@ -358,3 +358,7 @@ def set_api_client(new_client: client.ApiClient):
     global api_client, config_path
     api_client = new_client
     config_path = "custom"  # Mark as configured with custom client
+    # verify the client works by making a simple API call
+    client.AuthenticationApi(api_client).get_api_group()
+    # print message confirming successful configuration
+    print("Custom API client has been set and verified successfully.")