test(more): Fix test_from_line_option race condition by increasing PTY delay

[naoNao89]

Fixes test_from_line_option race condition by increasing delay from 100ms to 500ms, allowing more to fully render output before test reads PTY.

Fixes noise #9587

https://github.com/uutils/coreutils/actions/runs/20107767279/job/57697301129?pr=9587

[github-actions[bot]]

GNU testsuite comparison:

Skipping an intermittent issue tests/tail/overlay-headers (passes in this run but fails in the 'main' branch)