style: limit durabletask warnings for timers

## Expected Behavior

I have a workflow with external events, I have a timer configured for a timeout as seen below. I could not confirm if this is the root of all of the logs that I got, but my expected behavior is that if an unexpected timer is fired to not spam my logs.

```python
wf_completion_event = ctx.wait_for_external_event(event_name)
timeout_event = ctx.create_timer(timedelta(hours=24))
winner = yield when_any([wf_completion_event, timeout_event])
```

## Actual Behavior

I do not have the steps to reproduce this issue, but the couple of times it happened were after an activity had retried. My logs are spammed with +1k lines of warnings (snippet below) from a single request. Not sure if this is due to the timer I configured or something else.

```bash
2026-04-09 15:33:35.150 durabletask-worker WARNING: ac1d3d89-d79b-4d07-b86e-1f9d7d636081:0001: Ignoring unexpected timerFired event with ID = 5.
2026-04-09 15:33:35,150 - durabletask-worker - WARNING - ac1d3d89-d79b-4d07-b86e-1f9d7d636081:0001: Ignoring unexpected timerFired event with ID = 5.
2026-04-09 15:33:35.150 durabletask-worker WARNING: ac1d3d89-d79b-4d07-b86e-1f9d7d636081:0001: Ignoring unexpected timerFired event with ID = 5.
2026-04-09 15:33:35,150 - durabletask-worker - WARNING - ac1d3d89-d79b-4d07-b86e-1f9d7d636081:0001: Ignoring unexpected timerFired event with ID = 5.
2026-04-09 15:33:35.150 durabletask-worker WARNING: ac1d3d89-d79b-4d07-b86e-1f9d7d636081:0001: Ignoring unexpected timerFired event with ID = 5.
2026-04-09 15:33:35,150 - durabletask-worker - WARNING - ac1d3d89-d79b-4d07-b86e-1f9d7d636081:0001: Ignoring unexpected timerFired event with ID = 5.
```

acceptance criteria:
- [ ] this log is only logged once and is not contained within a loop that can spam our end users

## Steps to Reproduce the Problem

I do not know how to reproduce the error, apologies!

## Release Note

RELEASE NOTE: