Task ID synchronization error: "Task was specified but does not exist" in airbnb_planner_multiagent

### What happened?

The host agent was generating task IDs locally and sending them to remote agents (Weather Agent, Airbnb Agent) via the taskId field in message payloads. However, remote agents couldn't recognize these externally-generated task IDs because they expect to create their own tasks when receiving new messages, leading to JSONRPC errors.

_I have fixed the issue, I will be raising the PR soon._

### Relevant log output

```shell
JSONRPC error: Task was specified but does not exist

Added some custom logs to see the issue
# Host agent generating and sending task ID
🔑 Task ID: bbcd8576-d867-4296-8890-573d51da2fdc (from state)
✅ Added taskId to payload: bbcd8576-d867-4296-8890-573d51da2fdc

# Remote agent rejecting the unknown task ID
❌ Non-success response from 'weather_agent':
❌ Error details: Task bbcd8576-d867-4296-8890-573d51da2fdc was specified but does not exist
```

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