Stabilize wkld-sso-kubeconfig pipeline for tests due to timing, loading and element visibility

Test under test_download_workload_kubeconfig.py CI pipeline experiences intermittent failures.

The failures are non-deterministic — rerunning the same pipeline often passes without code changes. This suggests that the root cause is timing-related, likely due to inconsistent page load times, delayed DOM rendering, or unstable UI states.

wkld-sso-kubeconfig uses test_download_workload_kubeconfig.py playwright

This playwright can be improved by providing proper wait conditions.