Stabilize mgmt-GUIs-test pipeline for tests due to timing, loading and element visibility

The mgmt-GUIs-test CI pipeline experiences intermittent test failures across multiple test cases. 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.

mgmt-GUIs-test uses test_ui_playwright.py playwright

This playwright can be improved by providing proper wait conditions.

Also there is request here for improvement: !5934 (comment 2858212945) from @bogdan.antohe