Switches test_sync_streaming_with_functional_api to time.monotonic() for
both emitted task timestamps and observed arrival times so the assertion
is based on a monotonic clock instead of wall time. This makes the
streaming timing check less flaky on systems where time.time() can jump
or lack sufficient precision.
Created with [Deep Agents
CLI](https://docs.langchain.com/oss/python/deepagents/cli/overview)
using gpt-5.4 (provider: openai).
