Fix flaky test
=== RUN TestPropagateUntilStop
connection_test.go:38:
Error Trace: /Users/mike/src/gitlab-agent/internal/module/reverse_tunnel/agent/connection_test.go:38
Error: Unexpected context cancellation
Test: TestPropagateUntilStop
--- FAIL: TestPropagateUntilStop (0.00s)
Edited by Mikhail Mazurskiy