JS tests hanging at end of tests, sometimes causing CI test failures for "js" job

[dsyme]

JS tests seem to be hanging, maybe with dangling non-exited threads.

This is causing CI failures: https://github.com/github/gh-aw/actions/runs/24375689179/job/71188659429?pr=26136#step:7:480

✓ action_otlp.test.cjs (20 tests) 50ms
 ✓ safe_outputs_mcp_add_comment_constraints.test.cjs (18 tests) 67ms
 ✓ create_discussion_labels.test.cjs (10 tests | 1 skipped) 26ms
 ✓ parse_copilot_log.test.cjs (29 tests) 474ms
 ✓ cleanup_cache_memory.test.cjs (21 tests) 218ms
Error: The operation was canceled.

Find the cause of the problem and fix it.